D. G. Reina

A survey on probabilistic broadcast schemes for wireless ad hoc networks

Broadcast or flooding is a dissemination technique of paramount importance in wireless ad hoc networks. The broadcast scheme is widely used within routing protocols by a wide range of wireless ad hoc networks such as mobile ad hoc networks, vehicular ad hoc networks, and wireless sensor networks, and used to spread emergency messages in critical scenarios after a disaster scenario and/or an accidents. As the type broadcast scheme used plays an important role in the performance of the network, it has to be selected carefully. Though several types of broadcast schemes have been proposed, probabilistic broadcast schemes have been demonstrated to be suitable schemes for wireless ad hoc networks due to a range of benefits offered by them such as low overhead, balanced energy consumption, and robustness against failures and mobility of nodes. In the last decade, many probabilistic broadcast schemes have been proposed by researchers. In addition to reviewing the main features of the probabilistic schemes found in the literature, we also present a classification of the probabilistic schemes, an exhaustive review of the evaluation methodology including their performance metrics, types of network simulators, their comparisons, and present some examples of real implementations, in this paper.

A survey on multihop ad hoc networks for disaster response scenarios

Disastrous events are one of the most challenging applications of multihop ad hoc networks due to possible damages of existing telecommunication infrastructure. The deployed cellular communication infrastructure might be partially or completely destroyed after a natural disaster. Multihop ad hoc communication is an interesting alternative to deal with the lack of communications in disaster scenarios. They have evolved since their origin, leading to different ad hoc paradigms such as MANETs, VANETs, DTNs, or WSNs. This paper presents a survey on multihop ad hoc network paradigms for disaster scenarios. It highlights their applicability to important tasks in disaster relief operations. More specifically, the paper reviews the main work found in the literature, which employed ad hoc networks in disaster scenarios. In addition, it discusses the open challenges and the future research directions for each different ad hoc paradigm.

Modelling and assessing ad hoc Networks in disaster scenarios

Ad hoc networks have been proved to be suitable for disaster scenarios since any infrastructure needs to be deployed in order to establish a wireless network. Routing protocols play an important role in the performance of mobile ad hoc networks. Routing protocols are responsible for deciding how the information is going to move through the network. Although one paramount parameter of ad hoc networks is the mobility of nodes, little effort has been made to evaluate the performance of mobile ad hoc networks under mobility models where the movements of rescue teams during evacuating operations are modelled. The objective of this paper is to evaluate real case disaster scenarios in terms of performance using several well-known routing protocols metrics.

An evolutionary computation approach for optimizing connectivity in disaster response scenarios

This article presents an evolutionary computation approach for increasing connectivity in disaster scenarios. Connectivity is considered to be of critical importance in disaster scenarios due to constrained and mobile conditions. We propose the deployment of a number of auxiliary static nodes whose purpose is to increase the reachability of broadcast emergency packets among the nodes which are participating in the disaster scenario. These nodes represent people and vehicles acting in rescue operations. The main goal is to find the optimum positions for the auxiliary nodes, reinforcing the communications in points where certain lack of connectivity is found. These points will depend on the movements of the rescue teams, which are influenced by tactical reasons. Due to the complexity of the problem and the number of parameters to be considered, a genetic algorithm combined with the network simulator NS-2 is proposed to find the optimum positions of the auxiliary nodes. Specifically, NS-2 is used to model the communication layers and provide the fitness function guiding the genetic search. The proposed approach has been tested using the disaster mobility model included in the motion generator BonnMotion. The simulation results obtained demonstrate the feasibility of the proposed approach and illustrate its applicability in other scenarios where lack of connectivity is evident.

Hybrid Flooding Scheme for Mobile Ad Hoc Networks

A hybrid broadcast scheme for mobile wireless networks is proposed in this letter. The main objective is to combine different flooding schemes in order to solve the broadcast storm issue encountered by the simple flooding scheme. For this purpose, the density of nodes is taken into account using a density metric called expansion metric. In addition, in order to reduce the broken links due to mobility of nodes and increasing dissimilarity among the intermediate nodes, a forwarding zone criterion is included in the proposed schemes. The proposed approaches have been implemented and compared with pure probabilistic flooding, and simple flooding schemes.

Evaluation of Ad Hoc Networks in Disaster Scenarios

Ad hoc networks have been proved to be suitable for disaster scenarios since any infrastructure need to be deployed in order to establish a wireless network. Routing protocols play an important role in the performance of mobile ad hoc networks. Routing protocols are responsible for deciding how the information is going to move through the network. Although one paramount parameter of ad hoc networks is the mobility of nodes, little effort has been made to evaluate the performance of mobile ad hoc networks under mobility models which model the movements of rescue teams during evacuating operations. The objective of this paper is to evaluate real case disaster scenarios in terms of performance using several well-known routing protocols metrics.

Improving discovery phase of reactive ad hoc routing protocols using Jaccard distance

Recently, more and more research focus has been directed towards optimum designs for Mobile Ad Hoc Networks (MANETs). In this paper, the authors explore novel broadcasting schemes to improve the discovery phase of reactive routing protocols in MANETs. The objective is to reduce the redundancy of routing packets during the discovery phase of the reactive routing protocols for MANETs. For this purpose, the Jaccard distance is used to select dissimilar nodes during the discovery phase in order to reduce redundancy. Furthermore, it is shown that the Jaccard distance is correlated to the Euclidean distance. The simulation results obtained indicate that the Jaccard distance is a suitable metric for improving the discovery phase of the reactive routing protocols in MANETs.

Multi-objective performance optimization of a probabilistic similarity/dissimilarity-based broadcasting scheme for mobile ad hoc networks in disaster response scenarios

Communications among crewmembers in rescue teams and among victims are crucial to relieve the consequences and damages of a disaster situation. A common communication system for establishing real time communications between the elements (victims, crewmembers, people living in the vicinity of the disaster scenario, among others) involved in a disaster scenario is required. Ad hoc networks have been envisioned for years as a possible solution. They allow users to establish decentralized communications quickly and using common devices like mobile phones. Broadcasting is the main mechanism used to disseminate information in all-to-all fashion in ad hoc networks. The objective of this paper is to optimize a broadcasting scheme based on similarity/dissimilarity coefficient designed for disaster response scenarios through a multi-objective optimization problem in which several performance metrics such as reachability, number of retransmissions and delay are optimized simultaneously.

The Role of Ad Hoc Networks in the Internet of Things: A Case Scenario for Smart Environments

Internet of Things is an emerging area and it visions an inter-connected world full of physical as well as virtual objects, devices, processes and services capable of providing a different lens on how to link them via the Internet. While Internet of Things as part of the Future Internet has been described as a paradigm that mainly integrates and enables several technologies and communication solutions a notable interest is to define how current standard communication protocols could support the realization of the vision. Within this context, we offer a state-of-the-art review on ad hoc and wireless sensor networks, near field communications, radio frequency identification and routing protocols as a mean to describe their applicability towards an Internet of Things realization. We conclude by presenting a brief case scenario to describe a future smart environment and illustrate its possible model architecture.

A Survey on Ad Hoc Networks for Disaster Scenarios

This survey paper is intended to provide an overview of the main ad hoc paradigms that can be applied to disaster response networks, highlighting their applicability to important tasks in disaster relief operations. In this way, we also review the main works found in the literature which employed ad hoc networks in disaster scenarios. Finally, we provide open challenges and future research directions based on what has already been proved and what is still requiring further research.