Results for "Hesham Alfares"

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Optimum Bi-level Hierarchical Clustering for Wireless Mobile Tracking SystemsFeb 08 2019A novel technique is proposed to optimize energy efficiency for wireless networks based on hierarchical mobile clustering. The new bi-level clustering technique minimizes mutual interference and energy consumption in large-scale tracking systems used ... More
Iterative Clustering for Energy-Efficient Large-Scale Tracking SystemsFeb 08 2019A new technique is presented to design energy-efficient large-scale tracking systems based on mobile clustering. The new technique optimizes the formation of mobile clusters to minimize energy consumption in large-scale tracking systems. This technique ... More
Supervised learning based on temporal coding in spiking neural networksJun 27 2016Gradient descent training techniques are remarkably successful in training analog-valued artificial neural networks (ANNs). Such training techniques, however, do not transfer easily to spiking networks due to the spike generation hard non-linearity and ... More
Analytical Modeling of Mode Selection and Power Control for Underlay D2D Communication in Cellular NetworksMay 08 2014May 12 2014Device-to-device (D2D) communication enables the user equipments (UEs) located in close proximity to bypass the cellular base stations (BSs) and directly connect to each other, and thereby, offload traffic from the cellular infrastructure. D2D communication ... More
Single-Particle Spectrum of Pure Neutron MatterFeb 06 2015We have calculated the self-consistent auxiliary potential effects on the binding energy of neutron matter using the Brueckner Hartree Fock approach by adopting the Argonne V18 and CD-Bonn potentials. The binding energy with the four different choices ... More
On Stochastic Geometry Modeling of Cellular Uplink Transmission with Truncated Channel Inversion Power ControlJan 23 2014Using stochastic geometry, we develop a tractable uplink modeling paradigm for outage probability and spectral efficiency in both single and multi-tier cellular wireless networks. The analysis accounts for per user equipment (UE) power control as well ... More
Stochastic Interpretation of Quasi-periodic Event-based SystemsDec 09 2015Many networks used in machine learning and as models of biological neural networks make use of stochastic neurons or neuron-like units. We show that stochastic artificial neurons can be realized on silicon chips by exploiting the quasi-periodic behavior ... More
The Water-Filling Game in Fading Multiple Access ChannelsDec 03 2005We adopt a game theoretic approach for the design and analysis of distributed resource allocation algorithms in fading multiple access channels. The users are assumed to be selfish, rational, and limited by average power constraints. We show that the ... More
The Relay-Eavesdropper Channel: Cooperation for SecrecyDec 07 2006This paper establishes the utility of user cooperation in facilitating secure wireless communications. In particular, the four-terminal relay-eavesdropper channel is introduced and an outer-bound on the optimal rate-equivocation region is derived. Several ... More
Polar Coding for Secure Transmission and Key AgreementMar 06 2010Wyner's work on wiretap channels and the recent works on information theoretic security are based on random codes. Achieving information theoretical security with practical coding schemes is of definite interest. In this note, the attempt is to overcome ... More
Limits on the Capacity of In-Band Full Duplex Communication in Uplink Cellular NetworksNov 17 2015Simultaneous co-channel transmission and reception, denoted as in-band full duplex (FD) communication, has been promoted as an attractive solution to improve the spectral efficiency of cellular networks. However, in addition to the self-interference problem, ... More
The Three Node Wireless Network: Achievable Rates and Cooperation StrategiesJul 01 2005We consider a wireless network composed of three nodes and limited by the half-duplex and total power constraints. This formulation encompasses many of the special cases studied in the literature and allows for capturing the common features shared by ... More
Proactive Data Download and User Demand Shaping for Data NetworksApr 21 2013Dec 28 2014In this work, we propose and study optimal proactive resource allocation and demand shaping for data networks. Motivated by the recent findings on the predictability of human behavior patterns in data networks, and the emergence of highly capable handheld ... More
Harvesting Full-Duplex Rate Gains in Cellular Networks with Half-Duplex User TerminalsNov 01 2015Feb 28 2016Full-Duplex (FD) transceivers may be expensive in terms of complexity, power consumption, and price to be implemented in all user terminals. Therefore, techniques to exploit in-band full-duplex communication with FD base stations (BSs) and half-duplex ... More
Cooperative Lattice Coding and DecodingFeb 13 2006Feb 16 2006A novel lattice coding framework is proposed for outage-limited cooperative channels. This framework provides practical implementations for the optimal cooperation protocols proposed by Azarian et al. In particular, for the relay channel we implement ... More
Distributed Spectrum Sensing with Sequential Ordered Transmissions to a Cognitive Fusion CenterMay 30 2011Cooperative spectrum sensing is a robust strategy that enhances the detection probability of primary licensed users. However, a large number of detectors reporting to a fusion center for a final decision causes significant delay and also presumes the ... More
On the Secrecy Rate Region for the Interference ChannelMay 01 2009This paper studies interference channels with security constraints. The existence of an external eavesdropper in a two-user interference channel is assumed, where the network users would like to secure their messages from the external eavesdropper. The ... More
On Power Control and Frequency Reuse in the Two User Cognitive ChannelOct 16 2008This paper considers the generalized cognitive radio channel where the secondary user is allowed to reuse the frequency during both the idle and active periods of the primary user, as long as the primary rate remains the same. In this setting, the optimal ... More
Surrogate Gradient Learning in Spiking Neural NetworksJan 28 2019A growing number of neuromorphic spiking neural network processors that emulate biological neural networks create an imminent need for methods and tools to enable them to solve real-world signal processing problems. Like conventional neural networks, ... More
Cooperative encoding for secrecy in interference channelsMay 25 2009Apr 21 2011This paper investigates the fundamental performance limits of the two-user interference channel in the presence of an external eavesdropper. In this setting, we construct an inner bound, to the secrecy capacity region, based on the idea of cooperative ... More
Flexible Design for $α$-Duplex Communications in Multi-Tier Cellular NetworksNov 24 2015Apr 20 2016Backward compatibility is an essential ingredient for the success of new technologies. In the context of in-band full-duplex (FD) communication, FD base stations (BSs) should support half-duplex (HD) users' equipment (UEs) without sacrificing the foreseen ... More
ARQ Secrecy: From Theory to PracticeAug 17 2009Inspired by our earlier work on Automatic Repeat reQuest (ARQ) secrecy, we propose a simple, yet efficient, security overlay protocol to existing 802.11 networks. Our work targets networks secured by the Wired Equivalent Privacy (WEP) protocol because ... More
Proactive Resource Allocation: Harnessing the Diversity and Multicast GainsOct 21 2011This paper introduces the novel concept of proactive resource allocation through which the predictability of user behavior is exploited to balance the wireless traffic over time, and hence, significantly reduce the bandwidth required to achieve a given ... More
Proactive Resource Allocation: Turning Predictable Behavior into Spectral GainOct 09 2010This paper introduces the novel concept of proactive resource allocation in which the predictability of user behavior is exploited to balance the wireless traffic over time, and hence, significantly reduce the bandwidth required to achieve a given blocking/outage ... More
Cognitive MAC Protocols for General Primary Network ModelsJul 23 2009We consider the design of cognitive Medium Access Control (MAC) protocols enabling a secondary (unlicensed) transmitter-receiver pair to communicate over the idle periods of a set of primary (licensed) channels. More specifically, we propose cognitive ... More
Reactive Collision Avoidance using Evolutionary Neural NetworksSep 27 2016Collision avoidance systems can play a vital role in reducing the number of accidents and saving human lives. In this paper, we introduce and validate a novel method for vehicles reactive collision avoidance using evolutionary neural networks (ENN). A ... More
An event-based architecture for solving constraint satisfaction problemsMay 04 2015Constraint satisfaction problems (CSPs) are typically solved using conventional von Neumann computing architectures. However, these architectures do not reflect the distributed nature of many of these problems and are thus ill-suited to solving them. ... More
Unified Stochastic Geometry Model for MIMO Cellular Networks with RetransmissionsApr 11 2016This paper presents a unified mathematical paradigm, based on stochastic geometry, for downlink cellular networks with multiple-input-multiple-output (MIMO) base stations (BSs). The developed paradigm accounts for signal retransmission upon decoding errors, ... More
Blind Cognitive MAC ProtocolsOct 08 2008We consider the design of cognitive Medium Access Control (MAC) protocols enabling an unlicensed (secondary) transmitter-receiver pair to communicate over the idle periods of a set of licensed channels, i.e., the primary network. The objective is to maximize ... More
Rhythmic inhibition allows neural networks to search for maximally consistent statesMar 10 2015Gamma-band rhythmic inhibition is a ubiquitous phenomenon in neural circuits yet its computational role still remains elusive. We show that a model of Gamma-band rhythmic inhibition allows networks of coupled cortical circuit motifs to search for network ... More
Can Uplink Transmissions Survive in Full-duplex Cellular Environments?Apr 09 2016In-band full-duplex (FD) communication is considered a potential candidate to be adopted by the fifth generation (5G) cellular networks. FD communication renders the entire spectrum simultaneously accessible by uplink and downlink, and hence, is optimistically ... More
Using Network Coding to Achieve the Capacity of Deterministic Relay Networks with Relay MessagesApr 18 2014Apr 26 2014In this paper, we derive the capacity of the deterministic relay networks with relay messages. We consider a network which consists of five nodes, four of which can only communicate via the fifth one. However, the fifth node is not merely a relay as it ... More
On the Secrecy Capacity of Fading ChannelsOct 17 2006We consider the secure transmission of information over an ergodic fading channel in the presence of an eavesdropper. Our eavesdropper can be viewed as the wireless counterpart of Wyner's wiretapper. The secrecy capacity of such a system is characterized ... More
The Wiretap Channel with Feedback: Encryption over the ChannelApr 18 2007In this work, the critical role of noisy feedback in enhancing the secrecy capacity of the wiretap channel is established. Unlike previous works, where a noiseless public discussion channel is used for feedback, the feed-forward and feedback signals share ... More
Interference Management with Partial Uplink/Downlink Spectrum OverlapNov 19 2015Simultaneous reuse of spectral resources by uplink and downlink, denoted as in-band full duplex (FD) communication, is promoted to double the spectral efficiency when compared to its half-duplex (HD) counterpart. Interference management, however, remains ... More
Tractable Stochastic Geometry Model for IoT Access in LTE NetworksJul 12 2016The Internet of Things (IoT) is large-scale by nature. This is not only manifested by the large number of connected devices, but also by the high volumes of traffic that must be accommodated. Cellular networks are indeed a natural candidate for the data ... More
Spatiotemporal Stochastic Modeling of IoT Enabled Cellular Networks: Scalability and Stability AnalysisSep 17 2016Oct 29 2016The Internet of Things (IoT) is large-scale by nature, which is manifested by the massive number of connected devices as well as their vast spatial existence. Cellular networks, which provide ubiquitous, reliable, and efficient wireless access, are natural ... More
On Secrecy Capacity Scaling in Wireless NetworksAug 06 2009Apr 10 2010This work studies the achievable secure rate per source-destination pair in wireless networks. First, a path loss model is considered, where the legitimate and eavesdropper nodes are assumed to be placed according to Poisson point processes with intensities ... More
On the Delay Limited Secrecy Capacity of Fading ChannelsJan 19 2009May 01 2009In this paper, the delay limited secrecy capacity of the flat fading channel is investigated under two different assumptions on the available transmitter channel state information (CSI). The first scenario assumes perfect prior knowledge of both the main ... More
ARQ Security in Wi-Fi and RFID NetworksOct 15 2010In this paper, we present two practical ARQ-Based security schemes for Wi-Fi and RFID networks. Our proposed schemes enhance the confidentiality and authenticity functions of these networks, respectively. Both schemes build on the same idea; by exploiting ... More
Opportunistic Secrecy with a Strict Delay ConstraintJul 20 2009We investigate the delay limited secrecy capacity of the flat fading channel under two different assumptions on the available transmitter channel state information (CSI). The first scenario assumes perfect prior knowledge of both the main and eavesdropper ... More
Optimal Medium Access Protocols for Cognitive Radio NetworksFeb 19 2008This paper focuses on the design of medium access control protocols for cognitive radio networks. The scenario in which a single cognitive user wishes to opportunistically exploit the availability of empty frequency bands within parts of the radio spectrum ... More
Authentication over Noisy ChannelsFeb 19 2008In this work, message authentication over noisy channels is studied. The model developed in this paper is the authentication theory counterpart of Wyner's wiretap channel model. Two types of opponent attacks, namely impersonation attacks and substitution ... More
On The Security of AoA EstimationJul 02 2016Angle of Arrival (AoA) estimation has found its way to a wide range of applications. Much attention have been paid to study different techniques for AoA estimation and its applications for jamming suppression, however, security vulnerability issues of ... More
ARQ-Based Secret Key SharingOct 07 2008This paper develops a novel framework for sharing secret keys using existing Automatic Repeat reQuest (ARQ) protocols. Our approach exploits the multi-path nature of the wireless environment to hide the key from passive eavesdroppers. The proposed framework ... More
Spatiotemporal Stochastic Modeling of IoT Enabled Cellular Networks: Scalability and Stability AnalysisSep 17 2016The Internet of Things (IoT) is large-scale by nature, which is manifested by the massive number of connected devices as well as their vast spatial existence. Cellular networks, which provide ubiquitous, reliable, and efficient wireless access, are natural ... More
Secrecy Capacity of the Wiretap Channel with Noisy FeedbackOct 03 2007In this work, the role of noisy feedback in enhancing the secrecy capacity of the wiretap channel is investigated. A model is considered in which the feed-forward and feedback signals share the same noisy channel. More specifically, a discrete memoryless ... More
Modeling Cellular Networks with Full Duplex D2D Communication: A Stochastic Geometry ApproachAug 22 2016Full-duplex (FD) communication is optimistically promoted to double the spectral efficiency if sufficient self-interference cancellation (SIC) is achieved. However, this is not true when deploying FD-communication in a large-scale setup due to the induced ... More
In-Band Full-Duplex Communications for Cellular Networks with Partial Uplink/Downlink OverlapAug 12 2015Aug 25 2015In-band full-duplex (FD) communications have been optimistically promoted to improve the spectrum utilization in cellular networks. However, the explicit impact of spatial interference, imposed by FD communications, on uplink and downlink transmissions ... More
In-Band $α$-Duplex Scheme for Cellular Networks: A Stochastic Geometry ApproachSep 03 2015Jul 11 2016In-band full-duplex (FD) communications have been optimistically promoted to improve the spectrum utilization and efficiency. However, the penetration of FD communications to the cellular networks domain is challenging due to the imposed uplink/downlink ... More
Mobility-Aware Modeling and Analysis of Dense Cellular Networks with C-plane/U-plane Split ArchitectureJul 21 2016The unrelenting increase in the population of mobile users and their traffic demands drive cellular network operators to densify their network infrastructure. Network densification shrinks the footprint of base stations (BSs) and reduces the number of ... More
The MIMO Wireless Switch: Relaying Can Increase the Multiplexing GainJan 16 2009This paper considers an interference network composed of K half-duplex single-antenna pairs of users who wish to establish bi-directional communication with the aid of a multi-input-multi-output (MIMO) half-duplex relay node. This channel is referred ... More
A New Class of TAST Codes With A Simplified Tree StructureJan 19 2010Jan 21 2010We consider in this paper the design of full diversity and high rate space-time codes with moderate decoding complexity for arbitrary number of transmit and receive antennas and arbitrary input alphabets. We focus our attention to codes from the threaded ... More
Delay Asymptotics with Retransmissions and Incremental Redundancy Codes over Erasure ChannelsFeb 20 2012Recent studies have shown that retransmissions can cause heavy-tailed transmission delays even when packet sizes are light-tailed. Moreover, the impact of heavy-tailed delays persists even when packets size are upper bounded. The key question we study ... More
Optimal Medium Access Control in Cognitive Radios: A Sequential Design ApproachJan 21 2008The design of medium access control protocols for a cognitive user wishing to opportunistically exploit frequency bands within parts of the radio spectrum having multiple bands is considered. In the scenario under consideration, the availability probability ... More
Cognitive Medium Access: Exploration, Exploitation and CompetitionOct 06 2007This paper establishes the equivalence between cognitive medium access and the competitive multi-armed bandit problem. First, the scenario in which a single cognitive user wishes to opportunistically exploit the availability of empty frequency bands in ... More
Fingerprinting with Minimum Distance DecodingOct 15 2007This work adopts an information theoretic framework for the design of collusion-resistant coding/decoding schemes for digital fingerprinting. More specifically, the minimum distance decision rule is used to identify 1 out of t pirates. Achievable rates, ... More
On the Efficiency-vs-Security Tradeoff in the Smart GridSep 09 2012The smart grid is envisioned to significantly enhance the efficiency of energy consumption, by utilizing two-way communication channels between consumers and operators. For example, operators can opportunistically leverage the delay tolerance of energy ... More
Randomization for Security in Half-Duplex Two-Way Gaussian ChannelsAug 26 2009This paper develops a new physical layer framework for secure two-way wireless communication in the presence of a passive eavesdropper, i.e., Eve. Our approach achieves perfect information theoretic secrecy via a novel randomized scheduling and power ... More
Keys through ARQAug 01 2009This paper develops a novel framework for sharing secret keys using the well-known Automatic Repeat reQuest (ARQ) protocol. The proposed key sharing protocol does not assume any prior knowledge about the channel state information (CSI), but, harnesses ... More
Towards Jointly Optimal Placement and Delivery: To Code or Not to Code in Wireless Caching NetworksFeb 12 2019Coded caching techniques have received significant attention lately due to their provable gains in reducing the cost of data delivery in wireless networks. These gains, however, have only been demonstrated under the assumption of a free placement phase. ... More
Modeling Cellular Networks in Fading Environments with Dominant Specular ComponentsFeb 11 2016Feb 16 2016Stochastic geometry (SG) has been widely accepted as a fundamental tool for modeling and analyzing cellular networks. However, the fading models used with SG analysis are mainly confined to the simplistic Rayleigh fading, which is extended to the Nakagami-m ... More
A Diversity-Multiplexing-Delay Tradeoff of ARQ Protocols in The Z-interference ChannelFeb 08 2012Apr 03 2012In this work, we analyze the fundamental performance tradeoff of the single-antenna Automatic Retransmission reQuest (ARQ) Z-interference channel (ZIC). Specifically, we characterize the achievable three-dimensional tradeoff between diversity (reliability), ... More
Driver Distraction Identification with an Ensemble of Convolutional Neural NetworksJan 22 2019The World Health Organization (WHO) reported 1.25 million deaths yearly due to road traffic accidents worldwide and the number has been continuously increasing over the last few years. Nearly fifth of these accidents are caused by distracted drivers. ... More
Modeling and Analysis of Cellular Networks using Stochastic Geometry: A TutorialApr 13 2016This paper presents a tutorial on stochastic geometry (SG) based analysis for cellular networks. This tutorial is distinguished by its depth with respect to wireless communication details and its focus on cellular networks. The paper starts by modeling ... More
Interference Alignment for SecrecyOct 07 2008This paper studies the frequency/time selective $K$-user Gaussian interference channel with secrecy constraints. Two distinct models, namely the interference channel with confidential messages and the one with an external eavesdropper, are analyzed. The ... More
On the Secure Degrees of Freedom in the K-User Gaussian Interference ChannelMay 09 2008This paper studies the K-user Gaussian interference channel with secrecy constraints. Two distinct network models, namely the interference channel with confidential messages and the one with an external eavesdropper, are analyzed. Using interference alignment ... More
On the Diversity Gain Region of the Z-interference ChannelsFeb 12 2012Apr 03 2012In this work, we analyze the diversity gain region (DGR) of the single-antenna Rayleigh fading Z-Interference channel (ZIC). More specifically, we characterize the achievable DGR of the fixed-power split Han-Kobayashi (HK) approach under these assumptions. ... More
The Impact of Stealthy Attacks on Smart Grid Performance: Tradeoffs and ImplicationsDec 09 2014Jun 14 2016The smart grid is envisioned to significantly enhance the efficiency of energy consumption, by utilizing two-way communication channels between consumers and operators. For example, operators can opportunistically leverage the delay tolerance of energy ... More
Handover Management in 5G and Beyond: A Topology Aware Skipping ApproachNov 21 2016Network densification is found to be a potential solution to meet 5G capacity standards. Network densification offers more capacity by shrinking base stations' (BSs) footprints, thus reduces the number of users served by each BS. However, the gains in ... More
Designing a WISHBONE Protocol Network Adapter for an Asynchronous Network-on-ChipMar 19 2012The Scaling of microchip technologies, from micron to submicron and now to deep sub-micron (DSM) range, has enabled large scale systems-on-chip (SoC). In future deep submicron (DSM) designs, the interconnect effect will definitely dominate performance. ... More
Keys through ARQ: Theory and PracticeMay 27 2010May 28 2010This paper develops a novel framework for sharing secret keys using the Automatic Repeat reQuest (ARQ) protocol. We first characterize the underlying information theoretic limits, under different assumptions on the channel spatial and temporal correlation ... More
Handover Management in Dense Cellular Networks: A Stochastic Geometry ApproachApr 28 2016Cellular operators are continuously densifying their networks to cope with the ever-increasing capacity demand. Furthermore, an extreme densification phase for cellular networks is foreseen to fulfill the ambitious fifth generation (5G) performance requirements. ... More
A Unified Framework for Tree Search Decoding : Rediscovering the Sequential DecoderJun 09 2005We consider receiver design for coded transmission over linear Gaussian channels. We restrict ourselves to the class of lattice codes and formulate the joint detection and decoding problem as a closest lattice point search (CLPS). Here, a tree search ... More
Secrecy Outage Capacity of Fading ChannelsDec 13 2011This paper considers point to point secure communication over flat fading channels under an outage constraint. More specifically, we extend the definition of outage capacity to account for the secrecy constraint and obtain sharp characterizations of the ... More
Analysis of Reactivity Induced Accident for Control Rods Ejection with Loss of CoolingJun 05 2013Understanding of the time-dependent behavior of the neutron population in nuclear reactor in response to either a planned or unplanned change in the reactor conditions, is a great importance to the safe and reliable operation of the reactor. In the present ... More
Embedding LTE-U within Wi-Fi Bands for Spectrum Efficiency ImprovementJul 16 2016Driven by growing spectrum shortage, Long-term Evolution in unlicensed spectrum (LTE-U) has recently been proposed as a new paradigm to deliver better performance and experience for mobile users by extending the LTE protocol to unlicensed spectrum. In ... More
High Performance GNR Power Gating for Low-Voltage CMOS CircuitsJan 01 2019A robust power gating design using Graphene Nano-Ribbon Field Effect Transistors (GNRFET) is proposed using 16nm technology. The Power Gating (PG) structure is composed of GNRFET as a power switch and MOS power gated module. The proposed structure resolves ... More
Cooperative HARQ Assisted NOMA Scheme in Large-scale D2D NetworksJul 13 2017This paper develops an interference aware design for cooperative hybrid automatic repeat request (HARQ) assisted non-orthogonal multiple access (NOMA) scheme for large-scale device-to-device (D2D) networks. Specifically, interference aware rate selection ... More
Velocity-Aware Handover Management in Two-Tier Cellular NetworksSep 04 2016While network densification is considered an important solution to cater the ever-increasing capacity demand, its effect on the handover (HO) rate is overlooked. In dense 5G networks, HO delays may neutralize or even negate the gains offered by network ... More
Cooperative Handover Management in Dense Cellular NetworksJul 12 2016Network densification has always been an important factor to cope with the ever increasing capacity demand. Deploying more base stations (BSs) improves the spatial frequency utilization, which increases the network capacity. However, such improvement ... More
The Two-Way Wiretap Channel: Achievable Regions and Experimental ResultsJun 04 2010Oct 01 2011This work considers the two-way wiretap channel in which two legitimate users, Alice and Bob, wish to exchange messages securely in the presence of a passive eavesdropper Eve. In the full-duplex scenario, where each node can transmit and receive simultaneously, ... More