Lucia Gallina

A probabilistic energy-aware model for mobile ad-hoc networks

We propose a probabilistic, energy-aware, broadcast calculus for the analysis of mobile ad-hoc networks. The semantics of our model is expressed in terms of Segalas probabilistic automata driven by schedulers to resolve the nondeterministic choice among the probability distributions over target states. We develop a probabilistic observational congruence and a energy-aware preorder semantics. The observational congruence allows us to verify whether two networks exhibit the same observable probabilistic behaviour (connectivity), while the preorder is used to compare the energy consumption of different, but behaviourally equivalent, networks. As an application, we analyse and compare the energy consumption of two well-known automatic repeat request (ARQ)- based error control protocols: stop-and-wait (SW) and go-back-N (GBN).

Behavioural equivalences and interference metrics for mobile ad-hoc networks

Connectivity and communication interference are two key aspects in mobile ad-hoc networks (MANETs). This paper proposes a process algebraic model targeted at the analysis of both such aspects. The framework includes a probabilistic process calculus and a suite of analytical techniques based on a probabilistic observational congruence and an interference-sensitive preorder. The former enables the verification of behavioural equivalences; the latter makes it possible to evaluate the interference level of behaviourally equivalent networks. The result is a comprehensive and effective framework for the behavioural analysis and a quantitative assessment of interference for wireless networks in the presence of node mobility. We show our techniques at work on two realistic case studies.

Interference-Sensitive Preorders for MANETs

Connectivity and communication interference are two key aspects in mobile ad-hoc networks (MANETs). We propose a process algebraic model targeted at the analysis of both such aspects of MANETs. The framework includes a probabilistic process calculus and a suite of analytical techniques based on a probabilistic observational congruence and an interference-sensitive preorder. The observational congruence allows us to verify whether two networks exhibit the same behaviour. The preorder makes it possible to evaluate the interference level of different, behaviourally equivalent, networks. We show our framework at work on the analysis of the well-known Alternating Bit Protocol, contrasting the behavior of the standard implementation of the protocol against an alternative implementation that exploits an ideal interference cancellation scheme for CDMA transmissions.

A process calculus for energy-aware multicast communications of mobile ad hoc networks

Energy conservation is a critical issue in mobile ad hoc networks (MANETs) for both nodes and network lifetime, as only batteries power nodes. In this paper, we present the E-BUM calculus, an Energy-aware calculus for Broadcast, Unicast and Multicast communications of MANETs. In order to reason about cost-effective ad hoc routing protocols, our calculus captures the possibility for a node to control the transmission radius of its communications. We show how to use the E-BUM calculus in order to prove some useful connectivity properties of MANETs, to control network topology and to reason about the problem of reducing interference. In particular, we formalize the notions of sender-centred and receiver-centred interference and provide efficient proof techniques for verifying the absence of interference between a specific set of nodes. Copyright

Automatic energy-aware performance analysis of Mobile Ad-Hoc Networks

We present a framework to automatically evaluate the performance of Mobile Ad-hoc Networks (MANETs) in terms of different kinds of metrics, such as throughput and energy consumption. We use a probabilistic process calculus to model MANETs; we translate process terms into Markov Decision Processes (MDPs) and use the probabilistic model checker PRISM to automatically evaluate the network performance. We present a case study consisting of a network which uses flooding for communicating, and we analyse how time and energy costs vary when pursuing different power control strategies.

Sender- and receiver-centered interference in wireless ad hoc networks

Energy consumption in general and interference in particular are among the most critical issues in wireless networks. In this paper we present the E-BUM calculus, a Energy-aware calculus for Broadcast, Unicast and Multicast communications in wireless ad hoc networks. We formalize the notions of sender- and receiver-centered interference and provide efficient proof techniques for verifying the absence of interference between a specific set of nodes.

Evaluating resistance to jamming and casual interception in mobile wireless networks

Mobile ad-hoc and sensor networks play an important role in several application fields. The usage of wireless links and the node mobility make the networks prone to security attacks; among these, jamming attacks are insidious and they consist of one or more nodes continuously transmitting dummy packets to keep some wireless links busy. The goal is to destroy the network connectivity or highly reduce its throughput. In this paper we propose a probabilistic formal method, based on a process algebraic approach, targeted at the analysis of connectivity and the evaluation of interference in mobile networks. We show our framework at work on the analysis of an indoor wireless communication scenario.

A Calculus for Power-Aware Multicast Communications in Ad Hoc Networks

We present CMN#, a process calculus for formally modelling and reasoning about Mobile Ad Hoc Networks (MANETs) and their protocols. Our calculus naturally captures essential characteristics of MANETs, including the ability of a MANET node to broadcast a message to any other node within its physical transmission range, and to move in and out of the transmission range of other nodes in the network. In order to reason about cost-effective ad hoc routing protocols, we also allow unicast and multicast communications as well as the possibility for a node to control the transmission radius of its communications. We show how to use our calculus to prove some useful connectivity properties which can be exploited to achieve low-cost routing solutions.

A process algebraic framework for estimating the energy consumption in ad-hoc wireless sensor networks

We present a framework for modelling ad-hoc Wireless Sensor Networks (WSNs) and studying both their connectivity properties and their performances in terms of energy consumption, throughput and other relevant indices. Our framework is based on a probabilistic process calculus where system executions are driven by Markovian probabilistic schedulers, allowing us to translate process terms into discrete time Markov chains (DTMCs) and use the probabilistic model checker PRISM to automatically evaluate/estimate the connectivity properties and the energy costs of the networks. To the best of our knowledge, this is the first work that proposes a unique framework for studying qualitative (e.g., by proving the equivalence of components or the correctness of a behaviour) and quantitative aspects of WSNs using a tool that allows both exact and approximate (via Monte Carlo simulation) analyses. We demonstrate our framework at work by considering different communication strategies based on gossip routing protocols, for a typical topology and a mobility scenario.

Performance Analysis and Formal Verification of Cognitive Wireless Networks

Cognitive Networks are a class of communication networks, in which nodes can learn how to adjust their behaviour according to the present and past network conditions. In this paper we introduce a formal probabilistic model for the analysis of wireless networks in which nodes are seen as processes capable of adapting their course of action to the environmental conditions. In particular, we model a network made of mobile nodes using the gossip protocol, and we study how the energy performance of the network varies, according to the topology changes and the transmission power. The stochastic process underlying the model is a discrete time Markov chain. We use the PRISM model checker to obtain, through Monte-Carlo simulation, numerical results for our analysis, which show how the learning-driven dynamic adjustment of transmission power can improve the energy performance while preserving connectivity.