Evripidis Paraskevas

Multi-metric Energy Efficient Routing in Mobile Ad-Hoc Networks

Increasing network lifetime by reducing energy consumption across the network is one of the major concerns while designing routing protocols for Mobile Ad-Hoc Networks. In this paper, we investigate the main reasons that lead to energy depletion and we introduce appropriate routing metrics in the routing decision scheme to mitigate their effect and increase the network lifetime. For our routing scheme, we take into consideration multiple layer parameters, such as MAC queue utilization, node degree and residual energy. We integrate our multi-metric routing scheme into OLSR, a standard MANET proactive routing protocol. We evaluate via simulations in NS3 the protocol modifications under a range of different static and mobile scenarios. The main observations are that in static and low mobility scenarios our modified routing protocol leads to a significant increase (5%-20%) in network lifetime compared to standard OLSR and slightly better performance in terms of Packet Delivery Ratio (PDR).

Component based modeling of routing protocols for Mobile Ad Hoc Networks

Routing protocols perform several functionalities and can be considered as complex software systems. The design and performance analysis of these protocols is difficult and complex and most of them are not adaptable to changes of the environment. In this paper, we present a component based methodology for modeling mobile ad hoc routing protocols. Componentization is used for modeling and analysis of complex systems, because it introduces modularity in protocol design and reusability of designed components across protocols of the same class. We define the fundamental components of the routing protocols based on their functionalities and investigate their interactions. More specifically, we present an initial investigation of the influence of the separate components on the performance metrics of the protocol, such as delay, packet delivery ratio and routing overhead. Proactive routing protocols are being examined and we consider OLSR and DSDV as use cases for our methodology. In addition, we propose an adaptive reusable modification in the Routing Metrics component of OLSR that lead to better overall performance in energy constrained environments.

On the dynamics of linear functional differential equations with asymptotically constant solutions

We discuss the dynamics of general linear functional differential equations with solutions that exhibit asymptotic constancy. We apply fixed point theory methods to study the stability of these solutions and we provide sufficient conditions of asymptotic stability with emphasis on the rate of convergence. Several examples are provided to illustrate the claim that the derived results generalize, unify and in some cases improve the existing ones.

Convergence Analysis of Classes of Asymmetric Networks of Cucker-Smale Type with Deterministic Perturbations

We discuss two extensions of the Cucker-Smale flocking model with asymmetric coupling weights. The first model assumes a finite collection of autonomous agents aiming to perform a consensus process in the presence of identical internal dynamics. The second model describes a similar population of agents that perform velocity alignment with the restriction of collision-free orbits. Although qualitatively different, we explain how these models can be analyzed under a common framework. Rigorous analysis is conducted toward establishing sufficient conditions for asymptotic flocking to a synchronized motion. Applications of our results are compared with simulations to illustrate the effectiveness of our theoretical estimates.

Distributed sleep management for heterogeneous wireless machine-to-machine networks

Wireless machine-to-machine (M2M) communications are widely considered as part of the Internet of Things (IoT) infrastructure. Resource management is crucial for heterogeneous M2M networks. In this paper, we present new distributed sleep management techniques to prolong network lifetime for multi-hop heterogeneous wireless M2M networks, which consist of battery-powered nodes and mains-powered nodes. We also propose two novel battery energy aware routing metrics to efficiently select routes that satisfy performance guarantees. Finally, we present an extensive performance evaluation of our sleep management techniques and routing metrics. Simulation results show that our schemes achieve high packet delivery rate, long network lifetime and low energy consumption even in very low percentage of mains-powered nodes.

Distributed energy-aware mobile sensor coverage: A game theoretic approach

Mobile Sensor Networks (MSN) are used to monitor large areas and collect measurements, e.g. temperature, humidity, or pressure data. Mobile sensors try to optimize their benefit from sensing a particular area, while keeping their energy consumption at the lowest possible level. We formulate this energy-aware sensor coverage problem as a potential game, where the mobile sensor nodes are considered as agents. The utility function of the game captures the trade-off between the benefit from coverage and the energy consumption. We also propose a distributed learning strategy for this potential game. The algorithm enables a bit-valued information exchange between the agents. Finally, it is proved that the learning rule converges to a Nash Equilibrium.

QoS Aware Component-Based Routing in Resource-Constrained Wireless Multi-hop Networks

With an increasing number of wireless devices available, there is a tremendous need for designing new efficient protocols, which take into account resource constraints and at the same time provide adequate Quality of Service (QoS) performance guarantees (e.g. throughput, latency etc.). Most wireless protocols currently used perform well under specific environmental conditions or in particular applications. In this work, we propose a novel methodology for designing routing protocols for resource-constrained wireless multi-hop networks by separating the protocol into distinct components, which specify particular functionalities. Different QoS requirements can be guaranteed by configuring the different components without the need to modify or develop the protocol from scratch. An initial study for energy-constrained environments indicated that our approach is effective. In our ongoing work we consider adversarial environments and we develop techniques to mitigate network-layer attacks. Finally we are investigating the design of a decision-theoretic module for dynamic protocol configuration.