Although cooperative relaying has been widely utilized in wireless communications, it simultaneously introduces a new source of security vulnerabilities to the networks such as denial service attacks. In order minimize potential risks from relays, reliable relay authentication schemes become necessitated. this paper, novel scheme is proposed secure amplify-and-forward systems through utilizing device-dependent hardware imperfection in-phase/quadrature (I/Q) imbalance. scheme, I/Q imbalance...

We consider a half-duplex wireless relay network with hybrid-automatic retransmission request (HARQ) and Rayleigh fading channels. In this paper, we analyze the average throughput outage probability of multirelay delay-limited (DL) HARQ system an opportunistic relaying scheme in decode-and-forward (DF) mode, which best is selected to transmit source's regenerated signal. A simple distributed selection strategy considered for Then, utilize nonorthogonal cooperative transmission between source...

The performance of opportunistic relaying in a dual-hop amplify-and-forward relay network where the nodes are distributed according to homogeneous two-dimensional Poisson point process with fixed density is analyzed. Largely ignored literature, this assumption leads more realistic results, as typical practical scenario neither number relays nor their distances from source and destination known. An exact expression for outage probability cooperative system general fading environments...

I/Q imbalance commonly exists in direct conversion architecture based wireless transceivers due to the mismatches of analog components between in-phase (I) and quadrature (Q) branches. In this paper, device-dependent is utilized as transmitter fingerprint accomplish improved authentication through collaboration multiple receivers. precise, two hypothesis testing methods are proposed identify by using an related matrix. To enhance performance these methods, a multi-receiver scheme our study....

The dramatic increase in the network traffic data has become a major concern security systems. Intrusion detection systems (TDSs), as common widely used for communication networks, are not an exception. An IDS monitors to detect attacks through classifying into normal and abnormal classes. Due high dimensionality of data, it is always feasible intrusions quickly accurately. Feature selection emerges necessary step designing overcome its shortcoming enhance performance reduction complexity...

A novel virtual small cells formation approach for the fifth-generation mobile network is proposed in which a subset of qualified users selected to serve as base stations connecting other macrocell stations. In approach, optimum cell density obtained, so that number required communication links all directly or through minimized. It shown by using technique, connections becomes proportional logarithm user density. Since this relationship linear conventional cellular networks, utilization can...

The performance analysis of a wireless communication system on Nakagami-0.5 fading channels has importance, as it evaluates the in worst case scenario. This becomes more crucial when high level quality service is required. multi-hop amplify-and-forward relaying considered. First, shown that harmonic mean independent gamma random variables with shape parameter 0.5 again distribution same parameter. Then, using this fact, closed-form expressions giving accurate approximations for outage...

The performance of dual-hop opportunistic relaying with randomly distributed decode-and-forward relays is investigated. are assumed to be according a two-dimensional homogeneous Poisson point process, in contrast most the existing literature where locations known and deterministic. An exact expression for outage probability this cooperative system derived general fading environments. then specialized case transmission channels modeled as Rayleigh channels.

The achievable secrecy rate of a dual-hop amplify-and-forward relaying system, in the presence an eavesdropper, is investigated based on different values wireless links' signal-to-noise ratios (SNRs). It shown that when direct link to eavesdropper better condition than destination, but for destination under specific conditions links SNRs, it possible achieve limited range relay power. On other hand, certain not always beneficial employ relay, since there exists power which achievable....

Secrecy rate achievability in three-node amplify-and-forward cooperative systems at the presence of passive eavesdroppers without location information is statistically analyzed and optimized. First, effective vulnerability area, area which no secrecy achievable when an eavesdropper resides that introduced as performance metric to measure security system. Then, it shown analytically best relay minimize region on source-destination crossing line. In addition, proved optimum with power...

In this paper, we design an integrated protocol that jointly optimizes the performance of physical, medium access control (MAC), and network layers. Our goal is to minimize total energy consumption while delivering a minimum required signal-to-noise ratio (SNR) at each intended receiver within network. At MAC layer, develop cooperative automatic repeat request (ARQ) system, in which relay nodes assist source with its retransmission attempts. A complete analytic framework for system...

In this letter, probability of node to base station connectivity in a one-dimensional ad hoc network is calculated. It assumed that the location nodes follows homogeneous Poisson point process, while stations are either another independent process or with regular deployment. Nodes connected directly multi-hop fashion using other nodes. Analytical formulas obtained and compared by numerical results simulations.

The accuracy of two-reference-node angle-of-arrival localization system is investigated. First, the ambiguity area obtained in terms angles-of-arrival errors. Then, using this area, normalized precision defined to obtain target different positions with respect two reference nodes. In addition, for a given threshold, region which can be localized better than that threshold characterized and obtained.

The accuracy of centroid localization based on the connectivity information between a target node and multiple randomly scattered reference nodes is investigated. First, analyzed in general fading environment, it shown that ambiguity area this technique inversely proportional to density nodes. Additionally, at same order best case half provided by estimating location as its nearest node. Furthermore, increasing transmission power will increase localization, but only up certain limit. Then,...

The accuracy of the harmonic mean approximation (HMA) exact end-to-end signal-to-noise ratio (SNR) in multihop amplify-and-forward (AF) relaying systems is analyzed. A lower bound for SNR obtained as a function HMA. It shown that HMA overestimates value but no more than 0.5, regardless number hops and fading model being used. Then, performance bounds AF systems, including upper outage probability, average symbol error ergodic capacity, are using

In multihop relay networks with a large number of hops, it is challenging to allocate the available resources optimally among nodes due required control signals between controller and nodes. addition, latency caused by this signaling can result in using outdated resource-allocation information as channels are time varying. Hence, distributed scheme proposed for decode-and-forward (DF) systems, low complexity analytical computation practical implementation. Based on type division multiplexing...

In a wireless network, while the signal attenuation due to distance-related path loss is minimum between node and its nearest neighbor, this not case for overall when fading effect also taken into account. Hence, communication best neighbor (CBN) of defined as that with which it has highest channel power gain. Recently, statistics physical neighborhood index CBN have been derived general environment in nodes two-dimensional Poisson distribution. paper, distance well joint distance-index are...

The performance analysis of a wireless network significantly depends on the routing-related statistics. Power consumption, multihop communication delay, and position estimation are among parameters that affected by routing scheme. In this paper, statistical most forward within range in 1-D ad hoc networks investigated. Several parameters, such as probability mass function (pmf) number broadcast hops, density connectivity distance for given pmf hops between source destination, derived. For...

In many studies of amplify-and-forward cooperative networks, a harmonic mean approximation has been used for the instantaneous signal-to-noise ratio each dual hop relaying branch. This overestimates and results in lower bound performance metrics, such as outage probability average error probability. this paper, framework is introduced to obtain tight upper these function approximation. It shown that tightest possible one among all related approximations. derived by modifying same analysis...

The communication channel power gain to the nearest neighbor of a node in wireless network is not necessarily largest among all neighbors due fading. probability that kth has best with highest 2-D homogeneous Poisson distribution nodes derived for general fading environment. result specialized case where links are modeled as generalized-gamma channels. analytical results verified and illustrated by computer simulations numerical results. Some applications new theory also presented. A novel...

An exact expression for the outage probability of opportunistic relaying in a dual-hop amplify-and-forward relay network is derived general fading environments and case where source destination nodes make use directional antennas. The are assumed to be distributed according homogeneous two-dimensional Poisson point process with fixed density. This assumption great practical importance as typical scenario, number relays well their distances from random. It observed that under some...

Using the Global Positioning System (GPS) for indoor localization is challenging as GPS signal significantly attenuated or completely blocked by building. In achieving localization, a set of transmitters from wireless communication networks are often used reference nodes to localize target with unknown locations. The accuracy such process considerably affected spatial distribution respect node be localized. Hence, deploying at best locations will notably increase precision. this paper, novel...

Although cooperative relaying is generally considered as an attractive technique to improve system performances, the additional power consumption of a link becomes consistent concern. In order characterize dual-hop opportunistic with control, exact expression for cumulative distribution function total required transmission derived in this paper. Our analysis based on scenario that best relay selected among set decode-and-forward relays homogeneous spatial Poisson distribution, such...

A novel identity for the Gaussian Q-function of sum two non-negative variables is introduced as an extension Craig's formula. It shown that this new provides a unified framework in performance analysis dual-branch equal-gain combining (EGC) diversity, similar to formula maximum ratio diversity. Then, dual correlated branch EGC Nakagami-m fading studied using approach. For coherent modulations with error probabilities terms Q-function, it average probability same modeled single-channel...

The performance of a dual-hop amplify-and-forward (AF) relaying system in the presence jammer is analyzed by obtaining end-to-end outage probability for scenario where interference limited and operates either Nakagami-0.5 or Rayleigh fading environments. Then, optimal power allocation transmission toward relay destination maximizing analyzed. It shown that both environments when sufficiently large, jamming with equal optimal, whereas low, more should be allocated to jam any source-relay...