<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> This paper considers the transmission of confidential data over wireless channels. Based on an information-theoretic formulation problem, in which two legitimates partners communicate a quasi-static fading channel and eavesdropper observes their transmissions through second independent channel, important role is characterized terms average secure communication rates outage probability. insights...

We consider the transmission of confidential data over wireless channels with multiple communicating parties. Based on an information-theoretic problem formulation in which two legitimate partners communicate a quasi-static fading channel and eavesdropper observes their transmissions through another independent channel, we define secrecy capacity terms outage probability provide complete characterization maximum rate at is unable to decode any information. In sharp contrast known results for...

A thorough understanding of the communications channel between vehicles is essential for realistic modeling Vehicular Ad Hoc Networks (VANETs) and development related technology applications. The impact as obstacles on vehicle-to-vehicle (V2V) communication has been largely neglected in VANET research, especially simulations. Useful models accounting must satisfy a number requirements, most notably accurate positioning, mobility patterns, propagation characteristics, manageable complexity....

The theory of network coding promises significant benefits in performance, especially lossy networks and multicast multipath scenarios. To realize these practice, we need to understand how across packets interacts with the acknowledgment (ACK)-based flow control mechanism that forms a central part today's Internet protocols such as transmission protocol (TCP). Current approaches rateless codes batch-based are not compatible TCP's retransmission sliding-window mechanisms. In this paper,...

Smart cities aim to improve the citizens' quality of life by leveraging information about urban scale processes extracted from heterogeneous data sources collected on citywide deployments. The Internet-of-Things (IoT) is, thus, enabler smart city technologies at scale. In this paper, we present PortoLivingLab, a multisource sensing infrastructure that leverages IoT technology achieve city-scale four phenomena: weather, environment, public transport, and people flows. To sense these scale,...

We propose a mechanism that incorporates network coding into TCP with only minor changes to the protocol stack, thereby allowing incremental deployment. In our scheme, source transmits random linear combinations of packets currently in congestion window. At heart scheme is new interpretation ACKs - sink acknowledges every degree freedom (i.e., combination reveals one unit information) even if it does not reveal an original packet immediately. Such enable TCP-like sliding-window approach...

This paper presents a coding scheme for the Gaussian wiretap channel based on low-density parity-check (LDPC) codes. The messages are transmitted over punctured bits to hide data from eavesdroppers. proposed is asymptotically effective in sense that it yields bit-error rate (BER) very close 0.5 an eavesdropper whose signal-to-noise ratio (SNR) lower than threshold SNR <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">E</i> , even if has ability use...

Channel models for vehicular networks typically disregard the effect of vehicles as physical obstructions wireless signal. We aim to clarify validity this simplification by quantifying impact through a series experiments. Using two cars equipped with Dedicated Short Range Communications (DSRC) hardware designed use, we perform experimental measurements in order collect received signal power and packet delivery ratio information multitude relevant scenarios: parking lot, highway, suburban...

Inspired by recent results on information-theoretic security, we consider the transmission of confidential messages over wireless networks, in which legitimate communication partners are aided friendly jammers. We characterize security level a confined region quasi-static fading environment computing probability secrecy outage connection with two new measures physical-layer security: jamming coverage and efficiency. Our analysis for various strategies based different levels channel state...

While secrecy in communication systems has historically been obtained through cryptographic means the upper layers, recent research efforts have focused on physical layer and unveiled ample opportunities for security design. In particular, combination of signal processing techniques with channel coding central to development physical-layer efforts. Although implicit known since 1970s, explicit code constructions only discovered within last decade. The purpose this article is provide a...

The ability to exchange secret information is critical many commercial, governmental, and military networks. Information-theoretic security-widely accepted as the strictest notion of security-relies on channel coding techniques that exploit inherent randomness propagation channels strengthen security digital communications systems. Motivated by recent developments in field, we aim characterize fundamental secrecy limits wireless paper comprised two separate parts. In Part I, define...

Due to the dynamic nature of vehicular traffic and road surroundings, vehicle-to-vehicle (V2V) propagation characteristics vary greatly on both small- large-scale. Recent measurements have shown that large static objects (e.g., buildings foliage) as well mobile (surrounding vehicles) a profound impact V2V communication. At same time, system-level Vehicular Ad Hoc Network (VANET) simulators by employ simple statistical models, which do not account for surrounding explicitly. We designed...

We address the problem of localization in vehicular ad hoc networks. Our goal is to leverage vehicle communications and smartphone sensors improve overall performance. Assuming vehicles are equipped with IEEE 802.11p wireless interfaces, we employ a two-stage Bayesian filter track vehicle's position: an unscented Kalman for heading estimation using inertial sensors, particle that fuses vehicle-to-vehicle signal strength measurements received from mobile anchors whose positions uncertain,...

Consider the following network communication setup, originating in a sensor networking application we refer to as "sensor reachback" problem. We have directed graph G=(V,E), where V={v/sub 0/v/sub 1/...v/sub n/} and E/spl sube/V/spl times/V. If (v/sub i/,v/sub j/)/spl isin/E, then node i can send messages j over discrete memoryless channel (DMC) (X/sub ij/,p/sub ij/(y|x),Y/sub ij/), of capacity C/sub ij/. The channels are independent. Each v/sub i/ gets observe source information U/sub...

We consider the level of information security provided by random linear network coding in scenarios which all nodes comply with communication protocols yet are assumed to be potential eavesdroppers (i.e. "nice but curious"). For this setup, differs from wiretapping considered previously, we develop a natural algebraic criterion, and prove several its key properties. A preliminary analysis impact topology on overall security, particular for complete directed acyclic graphs, is also included.

Under the emerging network coding paradigm, intermediate nodes in are allowed not only to store and forward packets but also process mix different data flows. We propose a low-complexity cryptographic scheme that exploits inherent security provided by random linear offers advantage of reduced overhead comparison traditional end-to-end encryption entire data. Confidentiality is achieved protecting (or "locking") source coefficients required decode encoded data, without preventing from running...

Motivated by streaming applications with stringent delay constraints, we consider the design of online network coding algorithms timely delivery guarantees. Assuming that sender is providing same data to multiple receivers over independent packet erasure channels, focus on case perfect feedback and heterogeneous probabilities. Based a general analytical framework for evaluating decoding delay, show existing ARQ schemes fail ensure weak channels are able recover from losses within reasonable...

In Part I of this paper, we introduced the intrinsically secure communications graph (iS-graph)-a random which describes connections that can be established with strong secrecy over a large-scale network, in presence eavesdroppers. We focused on local connectivity iS-graph, and proposed techniques to improve it. second part, characterize maximum rate (MSR) achieved between node its neighbors. then consider scenario where eavesdroppers are allowed collude, i.e., exchange combine information....

A fundamental understanding of the delay behavior network coding is key towards its successful application in real-time applications with strict message deadlines. Previous contributions focused mostly on average decoding delay, which although useful various scenarios interest not sufficient for providing worst-case guarantees. To overcome this challenge, we investigate entire distribution random linear any field size and arbitrary number encoded symbols (or generation size). By introducing...

We consider the fundamental security limits of stochastic wireless networks in presence colluding eavesdroppers. By establishing a direct connection with single-input multiple-output (SIMO) Gaussian wiretap channel, we are able to provide complete characterization secrecy capacity for case which eavesdroppers scattered according spatial Poisson process. Our analysis, includes probabilities existence and outage capacity, helps clarify how density can jeopardize success physical-layer based on...

The experience of daily stress among bus drivers has shown to affect physical and psychological health, can impact driving behavior overall road safety. Although previous research consistently supports these findings, little attention been dedicated the design a detection method able synchronize physiological responses public in their day-to-day routine work. To overcome this limitation, we propose mobile sensing approach detect georeferenced facilitate memory recall stressful situations....

Vehicle-to-Vehicle (V2V) communication is a core technology for enabling safety and non-safety applications in next generation Intelligent Transportation Systems. Due to relatively low heights of the antennas, V2V often influenced by topographic features, man-made structures, other vehicles located between communicating vehicles. On highways, it was shown experimentally that can obstruct line sight (LOS) up 50 percent time; furthermore, single obstructing vehicle reduce power at receiver...

Motivated by recent developments in physical-layer security and stochastic geometry, we aim to characterize the fundamental limits of secure communication wireless networks. Based on a general model which legitimate nodes potential eavesdroppers are randomly scattered space, define graph (s-graph) from point view information-theoretic security. For Poisson s-graph, provide conclusive results for: (a) in-degree out-degree node; (b) isolation probability; (c) secrecy capacity between node each...