IoT healthcare systems aim to help patients to monitor their own condition and connect and interact with healthcare professionals. However, patients' privacy and sensitive data security are big issues which should be considered. Healthcare systems absolutely depend on 6G technologies due to its important characteristics. This paper provides a light mutual authentication and a secure data transmission in 6G/IoT healthcare system. Our proposal takes into account the emergency cases and non-emergency ones. We introduce a light authentication and a secure health data transmission between health service provider and health user. Then, we proceed a mutual authentication algorithm between health user and health collaborator followed by a light key agreement establishment. We prove the security of the protocol against several knowns' attacks. Then, we compare our proposed solution with other related works, the findings show the performance in terms of communication and computational.

Femtocells have progressively been employed to meet the needs of the forthcoming heterogeneous mobile systems (HetNets). However, the co-channel congestion between cells have soared to the extent that they hamper the effectiveness of thick HetNets. In this respective, Reinforcement learning (RL) can be a reliable tool to manage the assets in femtocell systems. In this paper, the HetNet is patterned as a multi-agent system in which the base station is deemed as an agent. In this context, A Qlearning Algorithm is proposed to efficiently cope with HetNets resources and to recognize the problem of large states space brought about by the aggregation of all agents states. In comparison with the previous works carried out in this context, this one is an attempt to boost Power control as well as the system-global capacity.

The ongoing deployment of 6G communications and the proliferation of Internet of Things (IoTs) faces several challenges such as user privacy and data security due to the huge number of intelligent IoT devices and intensive transmitted information in 6G network. Motivated by the above issues and the paramount importance of sensitive health data, in this paper, we present fast anonymous mutual authentication process for emergency healthcare system based on 6G/IoT network. The proposal does not include cloud trust authority when establishing mutual authentication. This, we guarantee data privacy, anonymous and lightweight authentication with low latency which are considered as the main feature of 6G/IoT communication. We prove the security of the protocol against several attacks. Then, we used AVISPA tool to validate security results. Moreover, the results demonstrate their performance in terms of communication and computational costs with respect to the relevant works.

In underlaid Device-to-Device (D2D) cellular networks, severe radio interference can be typical for cellular and D2D users, which causes each D2D user’s quality-of-experience (QoE) to degrade significantly. To remedy these problems, a dynamic Stackelberg game is proposed in this paper, where a single-leader (base station) and multiple-followers (cellular and D2D pairs) users are considered. Based on selection criteria jointly required by the base station, the cellular users and D2D users, a 2-stage Stackelberg game is investigated in this paper. In fact, the amount of power is first performed following a Nash Equilibrium at the first stage (base station). The derived amount power is then distributed among the other players (cellular and D2D users) relative to the proposed game, while respecting their heterogeneous criteria. Finally, power allocation and adjustment algorithms relative to the mentioned dynamic Stackelberg game will be investigated and compared with classical ones.

In spectrum sensing issues, like in any other classification problem, the performance of the classification task is significantly impacted by the feature selection. This paper proposes a new hybrid optimization algorithm to optimize feature selection for a Deep Neural Network (DNN) classifier. To surpass the premature convergence problem and improve the exploitation ability of the original Black Widow Optimization Algorithm (BWO), we mix a modified version of BWO and Particle Swarm Optimization (PSO), called MBWPSO. The aim is to enhance the performance of a blind spectrum sensing approach in the context of cognitive radio (CR) for wireless communications. Computer simulations show that the MBWPSO algorithm outperforms the original one and a set of state-of-the-art algorithms (i.e., HS, BBO, PSO, and SA) algorithms. The MBWPSO also exhibits the best performance once applied for feature selection in the above context

Long Term Evolution (LTE) standardization within the 3GPP has reached a mature state. Device-to-Device communication is a new technology that offer many advantages for the LTE-advanced network such as wireless peer-to-peer services and higher spectral efficiency. In fact, the D2D technologies aim to support the local discovery, identification and to enhance the network capacity and coverage. Near-far problem is one of the major issues that hurts mobile communications inadequately in 6G. This paper proposes a new green power control approach in 6G for a near far system, by modeling it as a non-cooperative game with pure strategies. A non-cooperative game, based on green communications, with statistical strategies is defined, which seek to balance between near and far players (users) belonging to the same Base Station, in terms of allocated power. Two cases are investigated for the proposed game: discrete and continuous, in order to reach both existence and uniqueness of the Nash Equilibrium. Finally, simulations are presented to compare the found results of the proposed games with the classic ones.

This paper proposes blind spectrum sensing (SS) in a narrowband context called Beamforming Fusion assisted Spectrum Sensing (BFSS). Considering a channel with angles of arrival (AoA), we jointly exploit beamforming algorithms to make decisions about the detection of users on frequency resources. The proposed method is totally blind and does not require knowledge of the noise power, the channel estimation, and the source signal. A state-of-the-art comparison of SS methods using beamforming is provided to validate our contribution in a shallow SNR region.

Abstract In cell‐free massive multiple‐input‐multiple‐output (CF‐MMIMO) systems, a massive number of access points, mastered by central processing units are distributed in a coverage area to serve much smaller number of user equipments (UEs) simultaneously over the same time/frequency resources. In opposition to the centralized MMIMO, CF‐MMIMO particularity is that its channel hardening degree is not sufficiently accentuated, thus, it will be judicious to include downlink (DL) pilots in order for the DL channel to be estimated. This paper considers the DL pilot assignment for the CF‐MMIMO systems by defining a metric, involving the inter‐user interference. This metric gives insights into DL pilot contamination. A threshold is then defined to optimize the number of DL pilots, which maximizes the minimum per‐user DL throughput. This approach gives a conflict graph, where each UE is regarded as a vertex of the graph. This is a combinatorial optimization problem that can be approximated using graph‐colouring algorithms. The simulation results reveal that the proposed method outperforms interestingly, in terms of per‐user DL throughput, the existing methods such as statistical channel state information, the orthogonal, and the random pilot assignment in the DL training.

A machine learning algorithm aims at designing a mathematical model based on a given training data set. Generally, the built model has a set of parameters that need to be adjusted. Since the performance of a given model depends on its settings, the parameters have to be carefully chosen through a fine-tuning step. A good model selection not only boosts performance but also allows a well-generalized model, i.e., a model that works sound on unseen data. In this paper, we assess the effectiveness of some metaheuristic optimization algorithms for support-vector machines (SVM) model selection. Computer simulations show that optimization algorithms that overall outperforms other algorithms using benchmark functions can be, further, definitely used for an efficient SVM model selection for classification. Thus, we show that Teaching–Learning-Based Optimization algorithm is faster and also enables the most accurate classification, even against other proposed methods in the literature for SVM model selection.

One of the main security issues in telecare medecine information systems is the remote user authentication and key agreement between healthcare professionals and patient’s medical sensors. Many of the proposed approaches are based on multiple factors (password, token and possibly biometrics). Two-factor authentication protocols do not resist to many possible attacks. As for three-factor authentication schemes, they usually come with high resource consumption. Since medical sensors have limited storage and computational capabilities, ensuring a minimal resources consumption becomes a major concern in this context. In this paper, we propose a secure and lightweight three-factor authentication and key generation scheme for securing communications between healtcare professional and patient’s medical sensors. Thanks to formal verification, we prove that this scheme is robust enough against known possible attacks. A comparison with the most relevant related work’s schemes shows that our protocol ensures an optimised resource consumption level.

E- Health systems, specifically, Telecare Medical Information Systems (TMIS), are deployed in order to provide patients with specific diseases with healthcare services that are usually based on remote monitoring. Therefore, making an efficient, convenient and secure connection between users and medical servers over insecure channels within medical services is a rather major issue. In this context, because of the biometrics' characteristics, many biometrics-based three factor user authentication schemes have been proposed in the literature to secure user/server communication within medical services. In this paper, we make a brief study of the most interesting proposals. Then, we propose a new three-factor authentication and key agreement scheme for TMIS. Our scheme tends not only to fix the security drawbacks of some studied related work, but also, offers additional significant features while minimizing resource consumption. In addition, we perform a formal verification using the widely accepted formal security verification tool AVISPA to demonstrate that our proposed scheme is secure. Also, our comparative performance analysis reveals that our proposed scheme provides a lower resource consumption compared to other related work's proposals.

Device-to-Device communication underlaying cellular network can improve the spectrum efficiency due to both direct proximity. Unlike previous works, which have dealt with potential and dynamic games etc.., we propose in this paper to study and to investigate both pure and mixed games, using two utility functions game of cellular and D2D users, in order to enhance the system spectral efficiency and to increase the SINR. First, we model each kind of users (D2D and Cellular users) as a rational player, aiming at maximizing its own net utility, based on the Quality of Service (QoS), in terms of Signal-to-Interference plus-Noise-Ratio (SINR) threshold. Second, pure and mixed games are investigated in this paper, where existence and uniqueness of the Nash equilibrium (NE) are studied. Finally, simulations are conducted to compare the proposed framework for the two kinds of proposed games.

Coding techniques that are employed to resolve packet losses on wireless channels, such as Random Linear Network Coding (RLNC), market themselves with the advantage of requiring less signalling, as well as, retransmissions of missing packets to compensate for losses on unreliable links. However, as packet sizes of IP-based protocols can be distributed irregularly over the available maximum frame size and can vary considerably packet-by-packet, the current implementations of RLNC suffer from shifting header and/or payload lengths and lack a suitable way of compensation. The simplest solution adopted by most RLNC approaches is to pad the unequal packets with zeros to the maximum packet size, thus creating an unnecessary transmission overhead of 100 % or more. This paper presents a practical implementation of the new progressive shortening based RLNC for the first time. This scheme utilizes fixed-sized regions inside the packets to resolve the zero-padding overhead and generates unequal-sized coded packets. Furthermore, it introduces a recoding feature for this scheme, which is another advantage of RLNC over other coding techniques, and breaks with the point-to-point topology considered in previous works. Moreover, we combine this novel macro-symbol based coding scheme with Robust Header Compression version 2 (RoHCv2) to show the gain over traditional implementation of RLNC in a real-life application where varying packet lengths dominate during transmissions. Our implementations results, using the KODO network coding library, show that the encoding throughput is as good as the established RLNC methods, and the payload delivery efficiency can be enhanced by up to 20 %.

In this article, we deal with the problem of understanding human-to-human interactions as a fundamental component of social events analysis. Inspired by the recent success of multi-modal visual data in many recognition tasks, we propose a novel approach to model dyadic interaction by means of features extracted from synchronized 3D skeleton coordinates, depth, and Red Green Blue (RGB) sequences. From skeleton data, we extract new view-invariant proxemic features, named Unified Proxemic Descriptor (UProD), which is able to incorporate intrinsic and extrinsic distances between two interacting subjects. A novel key frame selection method is introduced to identify salient instants of the interaction sequence based on the joints’ energy. From Red Green Blue Depth (RGBD) videos, more holistic CNN features are extracted by applying an adaptive pre-trained Convolutional Neural Networks (CNNs) on optical flow frames. For better understanding the dynamics of interactions, we expand the boundaries of dyadic interactions analysis by proposing a fundamentally new modeling for non-treated problem aiming to discern the active from the passive interactor. Extensive experiments have been carried out on four multi-modal and multi-view interactions datasets. The experimental results demonstrate the superiority of our proposed techniques against the state-of-the-art approaches.

The advancement in Information and Communication Technology (ICT), has led to the emergence of many new services. Like, the healthcare services which are generally based on Wireless Body Area Networks (WBAN). The data processed by WBAN nodes and transmitted over these networks is very sensitive. Thus, to ensure the development of eHealth systems, security must be guaranteed. Due to WBAN's constraints and limitations (e.g. computation, memory, and energy), a reliable security approach with optimal resource consumption must be established. The main objective of this work is to provide an optimal security approach for WBAN based on the use of biometrics (ECG: ElectroCardioGram). Indeed, the ECG will be used to generate and distribute, reliably and securely, symmetric cryptographic keys, on which the communication security will be based. The proposed approach is based on a time synchronisation method for the ECG signals availability within WBAN's sensors, and on three entities to create the biometric-key using an error-correcting code and a morphing function. In addition, our approach allows WBANs to optimise their resources consumption.

Ensuring privacy of transited data is a pillar need in Internet of Things (IoT) and Wireless Sensor Networks (WSN). In these networks, mutual authentication can help fulfilling trust and confidence of exchanged data between two communicating entities. In this paper, a Light and Trust Anonymous Mutual Authentication (LTAMA)- Algorithm for IoT is proposed. Then, a light shared key is settled between anonymous nodes. LTAMA-Algorithm design is based on Identity Based Encryption (IBE); Private Key Generator (PKG) and Elliptic Curve Cryptography (ECC). An evaluation of security performance is described to demonstrate the efficiency of LTAMA-Algorithm.

In this work, we investigate the MARC (Multiple Access Relay Channel) setup, in which two Markov sources communicate to a single destination, aided by one relay, based on Joint Source Channel Network (JSCN) LDPC codes. In addition, the two source nodes compress the information sequences with an LDPC source code. The compressed symbols are directly transmitted to both a relay and a destination nodes in two transportation phases. Indeed, the relay performs the concatenation of the received compressed sequences to obtain a recovered sequence, which is encoded with an LDPC channel code, before being forwarded to the destination. At the receiver, we propose an iterative joint decoding algorithm that exploits the correlation between the two sources-relay data and takes into account the errors occurring in the sources-relay links to estimate the source data. We show based on simulation results that the JSCN coding and decoding scheme into a MARC setup achieves a good performance with a gain of about 5 dB compared to a conventional LDPC code.

The key agreement protocol is essential to secure communication between communicating entities. However, the new constrained devices such as smart sensors do not support the existing key agreement due to the computation overheads. In addition, ensuring trust between entities is a challenge task in the network. In this paper, a light-weighted and trusted key agreement protocol is proposed between anonymous users. It guarantees safe communication with light computation cost. The new designed protocol is based on Identity Based Encryption (IBE); Private Key Generator (PKG) and Pseudonym Based Cryptography (PBC). Moreover, an evaluation of performance related to security and cost is discussed to prove the protocol's efficiency sheet.

In this paper, we design a unified framework decoder for relay systems with iterative decoding. In the proposed scheme, the source node needs to transmit a correlated content to a destination with the help of a relay. Then, a distributed Joint Source Channel (JSC) Low-Density-Parity-Check (LDPC) encoding is applied at the source and the relay. The destination receives simultaneously the source compressed data from the source node, and the source/channel encoded data from the relay node. The cooperative network is mapped into a factor graph on which message passing iterative decoding is applied to estimate the source information. The JSC decoder takes into account the source-relay correlation which involves remarkable improvements even if errors occur at the source-relay link. The Bit Error-Rate (BER) system performance are investigated for different scenario, according to the relay position, and it is shown that the performance of the proposed cooperative scheme is typically about 0.5–1.0 dB better than an equivalent rate point-to-point system.

Power Line Communication (PLC) channel is a fading channel whose their characteristics vary considerably over long distances and at high frequencies, therefore the major challenge, for the researchers, is how to supply robust and efficient communication in PLC systems. To overcome these constraints Cooperative Communication and Network Coding have been demonstrated to be effective techniques. Consequently in this paper, we consider a two-way relaying PLC system in which the Orthogonal Frequency Division Multiplexing (OFDM) is considered for the source 1-to-source 2, the source 1-to-relay and the relay-to-source 2 links where the relay node performs Amplify and Forward (AF) protocol. We propose a conventional bi-directional relaying schema (AF-PLC) which we compare to a schema including a Physical Network Coding (AF-PNC-PLC) for different number of time slots dedicated to exchange data messages between two source nodes S1and S2with the assistance of the relay node R. We also evaluate the data rate for OFDM-based two-way relaying AF-PLC and AF-PNC-PLC systems by applying the adaptive modulation technique.

In this paper, we study an electromagnetic optimization technique using Taguchi's method and apply it to circular antenna array (CAA) design. Taguchi's method was developed on the basis of the orthogonal array (OA) concept, which offers systematic and efficient characteristics. The newly proposed idea is the implementation of Taguchi optimization method for CAA of order 10, 16 and 24 respectively. The optimization procedure is then used to provide an optimum set of weights for different CAAs. Obtained results show that the desired radiation pattern with optimum sidelobe level (SLL) reduction is successfully achieved. Compared to traditional optimization techniques and well-known algorithms (Particle Swarm Optimization (PSO), Genetic Algorithm (GA), and Firefly Algorithm (FA)), Taguchi's method is easy to implement and efficient to reach the optimum solutions.

Security and privacy are prominent tasks in resource constrained devises in Internet of Things (IoT) and Wireless Sensor Networks (WSN). Therefore, to ensure anonymity and trust, concealing nodes' real identity trust management are mandatory. The majority of exiting IoT security solutions didn't achieve complete security needs and/or have large computation overheads. In this paper, STAC-protocol, a secure and trust anonymous communication protocol for IOT is presented. It is applied in clustered network to achieve sender, receiver and link anonymity and trusted communication. STAC-protocol is based on lightweight key agreement protocol; the Identity Based Encryption (IBE) and Pseudonym Based Encryption (PBC). A security analysis and performance evaluation are discussed to prove the protocol's enhancement.

As the size of Wireless Sensor Networks continues to grow, the amount of data for processing and transmitting becomes enormous. In many practical cases, the wireless sensors are distributed across a physical field to monitor physical phenomena with high space-time correlation. Compressive Sensing is a promising technique to exploit this correlation in order to limit the number of transmission and therefore increase the lifetime of the network. In this paper, we are interested in mesh network topology where the sink node is not in the range of sensors and routing schemes must be applied. We propose a joint Space-Time Compressive Sensing by exploiting jointly inter-sensor and intra-sensor data dependency. Since the routing and the number of retransmission affect significantly the total energy consumption, we introduce the routing in our cost function in order to optimize the selection of transmitting sensors. The simulations show that this method outperforms the existing ones and confirm the validity of our approach.

In this paper, we implement hybrid Woodward-Lawson Neural Networks and weighted Fourier method to synthesize antenna arrays. The neural networks (NN) is applied here to simplify the modeling of MIMO antenna arrays by assessing phases. The main problem is obviously to find optimal weights of the linear antenna array elements giving radiation pattern with minimum sidelobe level (SLL) and hence ameliorating the antenna array performance. To attain this purpose, an antenna array for reliable Multiple-Input Multiple-Output (MIMO) applications with frequency at 2.45 GHz is implemented. To validate the suggested method, many examples of uniformly excited array patterns with the main beam are put in the direction of the useful signal. The Woodward-Lawson Neural Networks synthesis method permits to find out interesting analytical equations for the synthesis of an antenna array and highlights the flexibility between the system parameters in input and those in output. The performance of this hybrid optimization underlines how well the system is suitable for a wireless communication and how it participates in reducing interference, as well.

Strong atmospheric turbulence can highly affect the free space optical (FSO) link. In fact, the strength of turbulence is depending on weather factors where the temperature is considered as the main parameter increasing these turbulences. In this work, an experimental investigation of the effect of Qatar's harsh climate on FSO link in term of packet ratio delivery (PDR) is carried out. Two FSO transceivers, operating June at 1550 nm for 600 m link distance, have been used. Based on Bendersky, Kopeika and Blaunstein (BKB) model and on the measured weather factors we tried to characterise the strength of turbulences under Qatar climate.

Inter-Cell Interference Coordination (ICIC) techniques are proposed as solutions to alleviate the negative impact of interference on system performance, while enhancing the provided Quality of Service (QoS). Typically, the available bandwidth is divided into inner and edge sub-bands. Users are also classified into interior and edge users. The available resources in each zone are exclusively allocated to users belonging to this zone. Mobile users classification is usually based on a threshold that can be either a given mean SINR value or a given distance. However, ICIC approaches based on these static parameters cannot efficiently manage non-homogeneous distribution of users. In this paper, we introduce a dynamic handoff algorithm that aims to adapt static ICIC schemes to uneven distribution of users. Our new solution dynamically computes the classification of active users into interior and edge users, based on a heuristic load balancing algorithm. In our proposal, each cell autonomously reconfigures its bandwidth allocation constraints without modifying bandwidth repartition across the cellular network. This makes the solution well adapted to the non-uniform repartition of users at the multicell scale. Simulation results show that the proposed scheme improves bandwidth usage, reduces packet delay, and increases user satisfaction compared to state-of-the-art ICIC techniques.

In this paper we are interested to the decoding of blocks turbo codes constructed from Reed Solomon (RS) codes. We have modified the iterative algorithm proposed by Chase in order to exploit the a priori information provided by a correlated source. Indeed, some sources such as images have a strong correlation. A simple iterative decoding algorithm does not take this feature into account. The choice of using RS turbo codes has an advantage compared to the BCH turbo codes when we focus on the example of the image, which is a good representative of correlated sources. A bijection between the pixels of the image and the symbols of the codes will be considered to introduce the bidirectional correlation in the iterative decoding of the rows and columns. Simulation results show that a significant performance gain is obtained with this type of decoding, compared to a classical RS turbo decoding, in case of correlated source and also in case of image transmission.

Powerline network is recognized as a favorable infrastructure for Smart Grid to transmit information in the network thanks to its broad coverage and low cost deployment. The existing works are trying to improve and adapt transmission techniques to reduce Powerline Communication (PLC) channel attenuation and exploit the limited bandwidth to support high data rate over long distances. Two-hop relaying BroadBand PLC (BB-PLC) system, in which Orthogonal Frequency Division Multiplexing (OFDM) is used, is considered in this paper. We derive and compare the PLC channel capacity and the end-to-end Average BER (ABER) for OFDM-based direct link (DL) BB-PLC system and for OFDM-based two-hop relaying BB-PLC system for Amplify and Forward (AF) and Decode and Forward (DF) protocols. We analyze the improvements when we consider the direct link in a cooperative communication when the relay node only transmits the correctly decoded signal. Maximum ratio combining is employed at the destination node to detect the transmitted signal. In addition, in this paper, we highlight the impact of the relay location on the channel capacity and ABER for AF and DF transmission protocols. Moreover, an efficient use of the direct link was also investigated in this paper.

Since PLC channel is a fading channel whose characteristics vary considerably over long distances and at high frequencies the major challenge for researchers in Smart Grid, is how to supply robust and efficient communication. To overcome these constraints Cooperative communication and Network coding have been demonstrated to be effective. Consequently in this paper, we consider a two-way relaying PLC system in which orthogonal frequency division multiplexing (OFDM) is employed for the source 1-to-source 2, the source 1-to-relay and the relay-to-source 2 links where the relay node performs Amplify and Forward (AF) protocol. We consider a conventional bi directional relaying schema (AF-PLC) and we compare it to a schema in which we include Physical Network Coding (AF-PNC-PLC) for different number of time slots dedicated to exchange data messages between two source nodes S1and S2with the assistance of the relay node R. We also derive the channel capacity and sum-average BER (SA-BER) expressions for OFDM-based two-way relaying AF-PLC and AF-PNC-PLC systems without and with cooperative diversity. Moreover, we provide a solution based on sub-carrier pairing technique to further improve the channel capacity and SA-BER performances.

A major challenge for researchers in Smart Grid, is how to supply robust and efficient communication since PLC channel is a fading channel whose characteristics vary considerably over long distances and at high frequencies. To overcome these constraints Cooperative communication and Network coding have been demonstrated to be effective. Consequently in this paper, we consider a two-way relaying network in which orthogonal frequency division multiplexing (OFDM) is employed for the source 1-to-source 2, the source 1-to-relay and the relay-to-source 2 links where the relay node performs Amplify and Forward (AF) protocol. We consider a conventional bi directional relaying schema (AF-PLC) and we compare it to a schema in which we include Physical Network Coding (AF-PNC-PLC) for different number of time slots dedicated to exchange data messages between two source nodes S1and S2with the assistance of the relay node R. We also evaluate the channel capacity for OFDM-based two-way relaying AF-PLC and AF-PNC-PLC systems without/with cooperative diversity. Moreover, we provide a solution based on sub-carrier pairing technique to further improve the channel capacity.

Multiple-Input Multiple-Output (MIMO) systems are very sensitive to carrier phase offset. In this paper, challenges regarding the provision of phase offset in orthogonal space time block codes (STBC) coded MIMO systems over Rayleigh fading channels are addressed. We develop a novel robust phase offsets estimation algorithm for MIMO systems based on STBC codes. Simulation results prove that the proposed phase offsets synchronizer provides accurate estimation.

A differential space-time block code (DSTBC) proves to be attractive alternative to the coherent space-time block code (STBC) due to providing blind detection. This paper proposes a novel blind detection of orthogonal STBC (OSTBC) scheme using rotated QPSK constellation for four transmit antennas. The proposed encoder is represented by a super trellis diagram. At the receiver side, the Viterbi algorithm is applied without channel state information (CSI). Simulation results demonstrate the good performance of the proposed method.

The concepts of array processing and smart antenna give a promising solution to the significant increase of data rates in wireless transmission systems. In this paper, we deal with the problem of designing linear antenna arrays for specific radiation properties of MIMO applications based on Direction-Of-Arrival estimation and Taylor beamforming techniques. The objectives of this paper can be summarized as to minimize the maximum sidelobe level (SLL), combined the Taylor method and MUSIC (Multiple Signal Classification) algorithm. The performance of this hybrid optimization determines how well the system is convenient for a reliable wireless communication and interference reduction. This paper will discuss the application of MUSIC algorithm for linear array antenna (4, 8 and 16 antennas) in order to estimate the Direction-Of-Arrival of various angles of elevation and azimuth.

Today's the paradigm for video compression has been significant development represented by the emergence of an important number of international standards efforts of ITU-TVCEG and ISO-IEC MPEG. The main objective of the current systems (such as the standards of MPEG-X and H-E6X) is to compress the original information in order to reduce the transmission rate.

It has been proven in the literature that the main technological factors limiting the communication rates of quantum cryptography systems by single photon are mainly related to the choice of the encoding method. In fact, the efficiency of the used sources is very limited, at best of the order of a few percent for the single photon sources and the photon counters can not be operated beyond a certain speed and with a low order of detection efficiency. In order to overcome partially these drawbacks, it is advantageous to use continuous quantum states as an alternative to standard encodings based on quantum qubits. In this context, we propose a new reconciliation method based on Turbo codes. Our theoretical model assumptions are supported by experimental results. Indeed, our method leads to a significant improvement of the protocol security and a large decrease of the QBER. The gain is obtained with a reasonable complexity increase. Also, the novelty of our work is that it tested the reconciliation method on a real photonic system under VPItransmissionMaker.

Security and privacy are challenging task in resource constrained in Internet of things (IoT) and Wireless Sensor Networks (WSN). Hence, anonymity and trust are prominent for many common IoT and WSN applications, in which we conceal nodes identity and give confidential data to a trusted node. The majority of exiting IoT security solutions cannot achieve complete security needs and/or have large computation overheads. In this paper we design a secure generic model for IoT and WSN to ensure anonymity, data secrecy and trust between nodes. Our work is based on lightweight key agreement protocol, the Identity Based Encryption (IBE) and Pseudonym Based Encryption (PBC).

Carrier-phase offset in multiple-input multiple-output (MIMO) systems is a significant practical and theoretical issue. In this paper, firstly we investigate the sensitivity of the space-time block code (STBC) to carrier-phase offset over Rayleigh flat fading MIMO channel. Then, we design an accurate third-order differential STBC (DSTBC) that allows the receiver to decode the data-symbols without any prior channel-state or any carrier-offset knowledge. This DSTBC detection scheme consists in a specific trellis diagram that involves constructive correlation between successive differential data-symbols that compensates for the channel-noise effect. At the receiver side, the well-known Viterbi algorithm designed with a particular metric provides reliable decoding process. The efficiency of the proposed scheme against random carrier-phase shift is also theoretically proven. Simulation results show the good performance of the DSTBC scheme for large carrier-phase offset range and also its ability to achieve high coding gain, as well. Negligible performance-loss from the coherent STBC scheme is also noticed.

Power Line Communication (PLC) remains the most appropriate communication architectures and technology for Smart Grid (SG) deployment. A major challenge for researchers in SG, is how to supply robust and efficient communication since PLC channel is a fading channel whose characteristics vary considerably over long distances and at high frequencies. To reach this goal, cooperative communication has been proven to be effective. Thus in this paper, we derive the channel capacity for OFDM-based two-hop relaying PLC system where we use a relay node between the source and destination nodes. We analyze channel capacity for Amplify-and-Forward (AF), Decode-and-Forward (DF) relaying protocols and Fountain-code-and-Forward (FCF) protocol which joint cooperative relay and coding techniques. We highlight in this paper how the use of this new category of cooperation relaying protocol (FCF) increases channel capacity of an OFDM-based two-hop relaying PLC system.

In this paper, we investigate the effect of the carrier phase offset on the performance of asymmetric M-ary shift keying (M-PSK) trellis coded modulation (TCM) over Rayleigh flat fading channel. For the purpose of comparison, the symmetric case is also discussed. A reliable low complexity non-data-aided (NDA) carrier phase recovery algorithm suited for general TCM schemes is designed here. We propose a recursive phase synchronization technique that dynamically tracks the fading channel variations and also exhibits an absolute minimum at the carrier phase offset. Simulation results show the efficiency of the resulting blind carrier phase synchronizer for symmetric and asymmetric 8-PSK TCM against blind phase estimators described in the literature. Also, it has negligible Bit Error Rate (BER) performance degradation as compared to the coherent system.

In this paper, challenges regarding the provision of channel state information (CSI) in multiple-input multiple-output (MIMO) systems based on space time block codes (STBC) over slow time-varying Rayleigh fading channels are addressed. We develop a novel MIMO channel estimation algorithm that adopts a pilot symbol assisted modulation (PSAM) which has been proven to be effective for fading channels. In this approach, pilot symbols are periodically inserted into the data stream that is sent through the orthogonal STBC encoder. At the receiver, we propose a straightforward MIMO channel estimation method before being used by STBC decoder. Simulation results indicate that the proposed pilot-assisted MIMO concept provides accurate channel estimates. The impact of Doppler frequency on performance scheme is also investigated by simulation.

In this paper, we propose a novel acoustic indoor localization system that is based on time reversal. The system estimates the target position with different precision. First, it uses a low frequency signal in order to localize the source in the whole area within coarse precision. Then, it switches to high frequency signal to estimate the target location in a reduced area within a fine precision. The system performance have been evaluated by simulations and by experiments conducted in a practical training room in the National School of Engineers of Le Mans. Results have shown that the system has subcentimeter accuracy.

Carrier phase offset is known as a serious drawback for trellis coded M-PSK systems. In this paper, we investigate the sensitivity of the 8-PSK- trellis coded modulation (8-PSK-TCM) to carrier phase offset over both additive white Gaussian noise (AWGN) and Rayleigh flat fading channels. Then, we design a reliable low complexity blind carrier phase recovery algorithm suited for general TCM schemes. The proposed estimation technique is based on a recursive phase metric that exhibits an absolute minimum at the carrier phase offset. Simulation results show the efficiency of the proposed non-data-aided (NDA) estimation technique for both AWGN and Rayleigh fading channels. The Bit Error Rate (BER) curves also exhibit acceptable performance loss compared to coherent schemes.

In this paper, we propose a novel acoustic localization system based on fingerprinting technique. It deploys the Time Of Arrival of CDMA signals emitted by speakers to locate a microphone. The system is inspired from our earlier proposed scheme [1] which deploys the lateration method. Here, we adopt the fingerprinting technique since it is more applicable to indoor environments. The position estimation is accomplished through nonparametric kernel regression. Performance are evaluated by experiments, performed in a hall of interns in National School of Engineers of Le Mans. Results have shown that our proposed scheme provides an accuracy of 8.5 cm within 80% precision.

The authors derive the true Cramér–Rao lower bound (CRLB) for a non-data-aided (NDA) carrier phase estimation from general M-ary phase-shift keying (M-PSK) modulation signal over flat Rayleigh fading channels (FRFC). The numerical Monte Carlo method is used to compute the true CRLB from general M-PSK modulation signals over FRFC with complex additive white Gaussian noise. The efficiency of the proposed method is made obvious through the assessment of the true CRLBs from both symmetric and asymmetric 8-PSK modulation signals for various observation window sizes. The simulation results show that optimal NDA carrier phase recovery is harder to acquire from symmetric modulation signals for signal-to-noise ratio (SNR) range up to 5 dB, but depends on the constellation density, only for SNR range superior to 5 dB. For both constellations the CRLB decreases as long as the observation window size increases. The derived bound provides an efficient standard for evaluating the performance of any unbiased NDA carrier phase estimator from general M-PSK modulation signals over FRFC. The method presented here stands useful for general M-ary quadrature amplitude modulation signals as well.

Most source coding standards (voice, audio, image and video) use Variable-Length Codes (VLCs) for compression. However, the VLC decoder is very sensitive to transmission errors in the compressed bit-stream. Previous contributions, using a trellis description of the VLC codewords to perform soft decoding, have been proposed. Significant improvements are achieved by this approach when compared with prefix decoding. Nevertheless, for realistic VLCs, the complexity of the trellis technique becomes intractable. In this paper, we propose a soft-input VLC decoding method using an a priori knowledge of the lengths of the source-symbol sequence and the compressed bit-stream with Maximum A Posteriori (MAP) sequence estimation. Performance in the case of transmission over an Additive White Gaussian Noise (AWGN) channel is evaluated. Simulation results show that the proposed decoding algorithm leads to significant performance gain in comparison with the prefix VLC decoding besides exhibiting very low complexity. A new VLC decoding method generating additional information regarding the reliability of the bits of the compressed bit-stream is also proposed. We consider the serial concatenation of a VLC with two types of channel code and perform iterative decoding. Results show that, when concatenated with a recursive systematic convolutional code (RSCC), iterative decoding provides remarkable error correction performance. In fact, a gain of about 2.3 dB is achieved, in the case of transmission over an AWGN channel, with respect to tandem decoding. Second, we consider a concatenation with a low-density parity-check (LDPC) code and it is shown that iterative joint source/channel decoding outperforms tandem decoding and an additional coding gain of 0.25 dB is achieved.

The application of distributed coding in many media applications, where low power and low-complexity encoder device is essential, is a new paradigm. In this paper, we propose a new pixel-domain Distributed Video Coding (DVC) scheme, in which both temporal and spatial correlations are exploited at the decoder. The Slepian-Wolf decoder is modified by introducing a source decoder to exploit Wyner-Ziv frame's spatial correlation. We assume the most significant bitplanes to be one-dimensional stationary markov process. The markov characteristic means that this source has a residual redundancy providing additional information for the receiver and can be exploited to correct some errors introduced by the virtual channel, through a joint source-channel decoding scheme.

A joint source channel coding scheme using bandwidth reducing has been proposed to optimize the mapping vector quantizer (VQ)-modulator symbols. The proposed two-step-algorithm optimizes first the mapping source codes-modulator symbols, and then optimizes VQ against the channel noise. To reach the target codebook size these steps are repeated iteratively. To show the proposed algorithm performance, it has been applied to transmission of a memoryless Gaussian source samples on Gaussian channel. The simulation results illustrate that a significant gain in terms of channel signal-to-noise ratio compared to a published result based on simulated annealing (SA) using a dynamic scaling of the signal. To show a subjective effect of the proposed two-step-algorithm a transmission over signal communication system including signal decomposition and mapping allocation is applied on flat fading channel.

In this paper a novel joint source channel (JSC) decoding technique is presented. The proposed approach enables iterative decoding for serially concatenated arithmetic codes and convolutional codes. Iterations are performed between Soft In Soft Out (SISO) component decoders. For arithmetic decoding, we proposed to employ a low complex trellis search technique to estimate the best transmitted codewords and generate soft outputs. Performance of the presented system are evaluated in terms of PER, in the case of transmission across the AWGN channel. Simulation results show that the proposed JSC iterative scheme leads to significant gain in comparison with a traditional separated decoding. Finally, the practical relevance of the proposed technique is validated under an image transmission system using the SPIHT codec.

In this paper, we propose a novel noncoherent UWB (de)modulation system, which uses a pair of orthogonal pulses to convey information symbols. Same as the original noncoherent UWB, our approach remains operational even without timing and channel estimation. Moreover, due to the orthogonality between the received waveforms of the pulse pair, our approach results in a differential demodulator. This means that our approach does not need Viterbi decoding which is required by, even in the presence of timing error. Simulations are also carried out to corroborate our theoretical analysis.

In this paper, we propose an efficient frequency reuse scheme for the downlink environment of multi-cell orthogonal frequency division multiplexing access (OFDMA) systems with 19-cell-structure, that provides an efficiency reduce of the co-channel interference (CCI) at the cell-edge region. It divides each cell into two regions: central region and edge region. The frequency reuse factor (FRF) is 1 in the central region and 3 in the edge region. The main contribution of this paper is to provide an optimal dimension of regions based on the maximization of the average to variance ratio of the signal to interference plus noise ratio (SINR) at mobile station receiver. Two optimization schemes are considered for the switching between central and edge regions: the first scheme is based on the distance between user and the serving base station and the second scheme is based on the received SINR level. A selection of simulation results are used to show the performance of the proposed scheme.

In this study, we consider Multi-user MISO systems based on Max-rate Limited Feedback Transmit Beamforming with B feedback bits. In the proposed idea, the Beamforming codebook {Wi}i=1N(N=2B) is divided into nDsub codebooks, such as D1,D2,..,DnD. At each channel use, the transmitter switches to a given sub-codebook adaptively to the user owning the worst case performance. Accordingly, the proposed scheme while minimizes the use of bandwidth of the feedback channel, enhances the fairness among users. Simulation results have been used to show the performance of the proposed scheme.

We propose a method to recover the structure of a randomly permuted chained code and how to cryptanalyse cryptographic schemes based on these kinds of error coding. This result prohibits the use of chained code on cryptography.

Compression of coronary angiographic images has been shown to be difficult as compared to other medical imaging modalities. Some of the factors partially responsible for this is the presence of complex detail structures that are only apparent by subtle changes in the contrast and altered by significant amount of noise. Simultaneous compression and denoising is required when images are altered by additive noise. In our work we developed a wavelet based comp-denoiser adapted to coronary X-ray images. The proposed approach consists on integrating an inter-scale dependant thresholding function, using Bayesian estimation theory, with WTCQ coding algorithm. Experimental results show that despite its simplicity and computational efficiency, our method yields a higher compression performance with a superior image quality. It also outperforms the state of the art of compression based denoisers in terms of distortion.

In this paper, an investigation of the behavior of the long semiconductor optical amplifiers (SOAs) in linear operating and saturation regimes is reported. Their exploitation feasibility for applications in high bit rate optical networks are therefore discussed. Hence, the impact of variation of the SOA active region length and the bias current on the saturation phenomena is analyzed referring to numerical simulations. It was shown that high saturation power feature, which is particularly required in wavelength division multiplexing (WDM) applications to avoid crosstalk arising from gain saturation effects, can be achieved by increasing the bias current.

This paper extends the geometrical one-ring multi- input multi output (MIMO) channel model for a frequency flat fading process in a land mobile radio system with respect to frequency-selectivity. Our approach enables the design of efficient simulation models for space-time MIMO channels under isotropic scattering conditions for any numbers of transmit and receive antennas. A simulation study is performed into the space- time cross correlation to gain understanding of the modification of some relevant parameters. A conventional four transmit four receive 4 x 4 MIMO radio channel is analyzed.

Timing acquisition is one of the major challenges in ultra-wideband (UWB) communications. The timing with dirty template (TDT) approach is an attractive technique for UWB systems, which is characterized by its low complexity and fast acquisition in the data-aided (DA) mode. However, in the non-data-aided (NDA) mode, the performance of this approach degrades due to the random symbol effect. In this paper, we propose to overcome this issue by adopting orthogonal pulse-shape modulation (PSM) proposed in L.B. Michael et al. (2002), (M. Pinchas and B.Z. Bobrovsky, 2003). Our algorithm uses a train of alternating orthogonal Hermite pulses to modulate the transmitted symbols. The application of the TDT approach to the proposed scheme shows an enhancement of synchronization speed in the NDA mode. Simulations confirm performance improvement of TDT with the proposed modulation relative to the original TDT in terms of the mean square error (MSE) and the acquisition probability.

Abstract Traditional fading mitigation techniques are designed relative to the worst‐case channel conditions, resulting in a poor utilization of the spectrum and the available power a good percentage of the time. In contrast, we introduce and investigate in this paper new adaptive modulation and diversity combining techniques that jointly select the most appropriate constellation size and the most suitable diversity branches in response to the channel variation and given a desired bit error rate (BER) requirement. Numerical results show that these newly proposed adaptive modulation and combining schemes can reduce considerably the average receiver channel estimation complexity as well as the power drain from the battery while offering high spectral efficiency and satisfying the desired outage probability and BER requirements. Copyright © 2006 John Wiley & Sons, Ltd.

It is pointed out in (1) that HFE is faster than RSA, but it has larger key storage. In this paper, we will outline some of its advantages and disadvantages. We will also study the fact of the extension field degree and the private key degree on the speed of key generation, encryption and decryption.

With the blossoming demand for efficiently storing and transmitting digital information, image compression has been increasingly vital. On the other hand, at very low bitrates, lossy compression is supposed to be a strong attack to watermarking process. In this work, we attempt to integrate watermarking in wavelet-based image coding. In our study, we used three different wavelet-based compression techniques. The last two coders are respectively included in part I and part II of JPEG2000 standard. Taking advantage of the coding architecture, a watermark embedding is directly performed on the wavelet coefficients before the quantization phase. On the recovery stage, the hide information may be retrieved during the decoding or where ever we decompose the reconstructed image on its wavelet domain. Experimental results have shown that blind watermarking coupled with JPEG2000-based image coders exhibits a high robustness to compression attacks with respect to the quality of the reconstructed images. Moreover, its time consuming is negligible compared to coding and decoding duration

Traditional fading mitigation techniques are designed relative to the worst-case channel conditions, resulting in a poor utilization of the spectrum and the available power a good percentage of the time. In contrast, we introduce and investigate in this paper new adaptive modulation and diversity combining techniques that jointly select the most appropriate constellation size and the most suitable diversity branches in response to the channel variation and given a desired bit error rate (BER) requirement. Numerical results show that these newly proposed adaptive modulation and combining schemes can reduce considerably the average receiver channel estimation complexity as well as the power drain from the battery while offering full spectral efficiency and satisfying the desired outage probability and BER requirements.

The paper is concerned with the scaling behavior of a scattering function of an HF channel. The non homogeneity of the scattering function expressed according to the time propagation and Doppler shift led us to split it into two one dimensional vectors. We have studied their scale dependent properties over global and local scaling analysis. As an example, we have studied the ionospheric channel. Based on multifractal formalism combined with the discrete wavelet transform, we have proved the multifractality of the ionospheric scattering function and detected the presence of a long-range-dependence phenomenon. Also, we have shown the existence of a cut-off scale below which the scaling behavior no longer holds. These results are very useful for further HF channel modelling.

We have developed a new multifractal modelling framework, called complex multifractal dimension, for characterizing the HF channel. Using the wavelet packet decomposition, and a special fractal dimension algorithm, the complex multifractal dimension provides a local characterization and a coherent physical interpretation, contrarily to others multifractal spectrums. We have adopted the scattering function as a tool for the ionosphere channel characterization. The non-homogeneity of the scattering function expressed according to the propagation time and Doppler shift led us to split it into two one dimensional vectors. Our analysis was performed over both theoretical examples and experimental scattering functions of the ionospheric channel obtained with an experimental support: STUDIO station.

In this paper we present a performance study of an input/output buffered type ATM switch with backpressure mechanism with an MMPP process as input. The backpressure is exerted at the Head of Line (HOL) level to prevent output buffer cell loss. MMPP process is chosen due to its bursty nature able to capture multimedia source characteristics such as data and voice. We propose an approximate method to calculate the total waiting time in the switch. Numerical examples will be given for two states MMPP to quantitatively show the effects of output buffer size b on performance switch. The analysis is done by using structured stochastic matrices of M/G/I type and the obtained results extend those related to scalar case (Poisson process).