Manel Guerrero Zapata

Secure ad hoc on-demand distance vector routing

This article gives an overview of different approaches to provide security features to routing protocols in mobile ad hoc networks (MANET). It also describes Secure AODV (an extension to AODV that provides security features) giving a summary of its operation and talking about future enhancements to the protocol.

Wireless Multimedia Sensor Networks: Current Trends and Future Directions

Wireless Multimedia Sensor Networks (WMSNs) have emerged and shifted the focus from the typical scalar wireless sensor networks to networks with multimedia devices that are capable to retrieve video, audio, images, as well as scalar sensor data. WMSNs are able to deliver multimedia content due to the availability of inexpensive CMOS cameras and microphones coupled with the significant progress in distributed signal processing and multimedia source coding techniques. In this paper, we outline the design challenges of WMSNs, give a comprehensive discussion of the proposed architectures, algorithms and protocols for the different layers of the communication protocol stack for WMSNs, and evaluate the existing WMSN hardware and testbeds. The paper will give the reader a clear view of the state of the art at all aspects of this research area, and shed the light on its main current challenges and future trends. We also hope it will foster discussions and new research ideas among its researchers.

Review: Security on VANETs: Privacy, misbehaving nodes, false information and secure data aggregation

This article is a position paper on the current security issues in Vehicular Ad hoc Networks (VANETs). VANETs face many interesting research challenges in multiple areas, from privacy and anonymity to the detection and eviction of misbehaving nodes and many others in between. Multiple solutions have been proposed to address those issues. This paper surveys the most relevant while discussing its benefits and drawbacks. The paper explores the newest trends in privacy, anonymity, misbehaving nodes, the dissemination of false information and secure data aggregation, giving a perspective on how we foresee the future of this research area. First, the paper discusses the use of Public Key Infrastructure (PKI) (and certificates revocation), location privacy, anonymity and group signatures for VANETs. Then, it compares several proposals to identify and evict misbehaving and faulty nodes. Finally, the paper explores the differences between syntactic and semantic aggregation techniques, cluster and non-cluster based with fixed and dynamic based areas, while presenting secure as well as probabilistic aggregation schemes.

Game theory for energy efficiency in Wireless Sensor Networks

In the area of Wireless Sensor Networks (WSNs), improving energy efficiency and network lifetime is one of the most important and challenging issues. Most of the considered WSNs are formed by nodes with limited resources, in which each node plays dual rule of both sensing the environment and relaying traffic to the sink from other nodes. On the one hand, the nodes need to stay alive as long as possible by achieving energy efficiency. On the other hand, they have to provide the required service. This conflict of interest makes game theory very useful in WSNs. Moreover, nodes usually have to make decisions with limited information about the state of the network. Game theory has been used recently in a remarkable amount of research in this area. In this survey, we review the most recent papers about using game theory in WSNs to achieve a trade-off between maximizing the network lifetime and providing the required service. The paper contains a complete taxonomy of games applied to this specific research problem. It summarizes and compares the different published proposals along with tables and statistical charts showing in which domains game theory has been applied recently. Overall, the paper will give to researchers a clear view of the newest trends in this research area, underlining its main challenges and hopefully fostering discussions and new research directions.

A Secure Cluster-Based Multipath Routing Protocol for WMSNs

The new characteristics of Wireless Multimedia Sensor Network (WMSN) and its design issues brought by handling different traffic classes of multimedia content (video streams, audio, and still images) as well as scalar data over the network, make the proposed routing protocols for typical WSNs not directly applicable for WMSNs. Handling real-time multimedia data requires both energy efficiency and QoS assurance in order to ensure efficient utility of different capabilities of sensor resources and correct delivery of collected information. In this paper, we propose a Secure Cluster-based Multipath Routing protocol for WMSNs, SCMR, to satisfy the requirements of delivering different data types and support high data rate multimedia traffic. SCMR exploits the hierarchical structure of powerful cluster heads and the optimized multiple paths to support timeliness and reliable high data rate multimedia communication with minimum energy dissipation. Also, we present a light-weight distributed security mechanism of key management in order to secure the communication between sensor nodes and protect the network against different types of attacks. Performance evaluation from simulation results demonstrates a significant performance improvement comparing with existing protocols (which do not even provide any kind of security feature) in terms of average end-to-end delay, network throughput, packet delivery ratio, and energy consumption.

A Cross-Layer-Based Clustered Multipath Routing with QoS-Aware Scheduling for Wireless Multimedia Sensor Networks

Wireless multimedia sensor networks (WMSNs) can handle different traffic classes of multimedia content (video, audio streams, and still images) as well as scalar data over the network. To ensure correct delivery of real-time multimedia data and efficient resource utilization, a proposed solution should provide both quality of service (QoS) assurance and energy efficiency. In this paper, we propose a cross-layer-based routing protocol that can utilize MAC-layer QoS-based scheduling for more efficient routing mechanism in WMSNs. Our proposed optimization is based on clustered multipath routing protocol and adaptive QoS-aware scheduling for the different traffic classes in WMSNs. Our design exploits the hierarchical structure of powerful cluster heads and the optimized multiple paths along with the adaptive scheduling to support reliable, high-throughput, and energy-efficient multimedia transmission in WMSNs. Simulation results show a significant performance improvement of our proposed design when compared to other similar routing schemes.

Shortcut detection and route repair in ad hoc networks

When a routing protocol for MANET networks (mobile and ad hoc networks) does a route discovery, it does not discover the shortest route but the route through which the route request flood traveled faster. In addition, since nodes are moving, a route that was the shortest one at discovery time might stop being so in quite a short period of time. This causes, not only a much bigger end-to-end delay, but also more collisions and a faster power consumption. In order to avoid all the performance loss due to these problems, this paper develops a technique to periodically discover shortcuts to the active routes that can be used with any destination vector routing protocol. It also shows how the same mechanism can be used as a bidirectional route recovery mechanism.

Energy efficiency of MAC protocols in low data rate wireless multimedia sensor networks: A comparative study

Some new application scenarios for Wireless Sensor Networks (WSNs) such as urban resilience, smart house/building, smart agriculture and animal farming, among others, can be enhanced by adding multimedia sensors able to capture and transmit small multimedia samples such as still images or audio files. In these applications, Wireless Multimedia Sensor Networks (WMSNs) usually share two conflicting design goals. On the one hand, the goal of maximizing the network lifetime by saving energy, and on the other, the ability to successfully deliver packets to the sink. In this paper, we investigate the suitability of several WSNs MAC protocols from different categories for low data rate WMSNs by analyzing the effect of some network parameters, such as the sampling rate and the density of multimedia sensors on the energy consumption of nodes. First, we develop a general multi-class traffic model that allows us to integrate different types of sensors with different sampling rates. Then, we model, evaluate and compare the energy consumption of MAC protocols numerically. We illustrate how the MAC protocols put some constraints on network parameters like the sampling rates, the number of nodes, the size of the multimedia sample and the density of multimedia nodes in order to make collisions negligible and avoid long queuing delays. Numerical results show that in asynchronous MAC protocols, the receiver-initiated MAC protocols (RI-MAC and PW-MAC) consume less energy than the sender-initiated ones (B-MAC and X-MAC). B-MAC outperforms X-MAC when the sampling rates of multimedia nodes is very low and the polling periods are short. PW-MAC shows the lowest energy consumption between the selected asynchronous MAC protocols and it can be used in the considered WMSNs with a wider range of sampling rates. Regarding synchronous MAC protocols, results also show that they are only suitable for the considered WMSNs when the data rates are very low. In that situation, TreeMAC is the one that offers the lowest energy consumption in comparison to L-MAC and T-MAC. Finally, we compare the energy consumption of MAC protocols in four selected application scenarios related to Smart Cities and environment monitoring.

A reputation-based centralized energy allocation mechanism for microgrids

The increasing energy prices and the need to provide energy security during emergencies have pushed researchers and companies to find smarter and more sustainable solutions. In this context, microgrids appear to be increasingly popular. In this paper we present an energy sharing framework for microgrids in which houses share their renewable energy, harvested from some kind of on-site renewables, by transmitting it to an Energy Management Center (EMC). In each time period, the EMC collects the renewable energy and stores it in a central storage unit. It also receives power requests from demanding houses and manages distribution. How to achieve a fair and efficient energy allocation is a challenging problem. For this purpose, we propose a reputation-based energy distribution mechanism that allows the EMC to allocate energy to houses when they request it according to their reputation. We apply our mechanism over three different classes of households. Simulation results show that our energy sharing framework improves the utilization of renewable energy and that the proposed energy allocation mechanism achieves fairness. It is also expected to promote energy conscious behavior as houses will receive energy in proportion to their contribution and energy consumption behavior.

Citizens collaboration to minimize power costs in smart grids: A game theoretic approach

Generating the power necessary to run our future cities is one of the major concerns for scientists and policy makers alike. The increasing global energy demands with simultaneously decreasing fossil energy sources will drastically affect future energy prices. Strategies are already being implemented to develop solutions for the generation and efficient usage of energy at different levels. Involving citizens in the efficient planning and usage of power is a key. In this paper, we propose a game theory based power sharing mechanism between end-users in smart grids. We consider that citizens can produce some amount of electric power obtained from on-site renewable sources rather than just purchasing their whole demands from the grid. Simulation results show that consumers can achieve considerable cost savings if they adopt the proposed scheme. It is also noticed that the more the consumers cooperate, the higher the percentage of cost savings is.