Dynamic Network State Learning Model for Mobility Based WMSN Routing Protocol

The rising demand of wireless multimedia sensor networks (WMSNs) has motivated academia-industries to develop energy efficient, Quality of Service (QoS) and delay sensitive communication systems to meet major real-world demands like multimedia broadcast, security and surveillance systems, intelligent transport system, etc. Typically, energy efficiency, QoS and delay sensitive transmission are the inevitable requirements of WMSNs. Majority of the existing approaches either use physical layer or system level schemes that individually can’t assure optimal transmission decision to meet the demand. The cumulative efficiency of physical layer power control, adaptive modulation and coding and system level dynamic power management (DPM) are found significant to achieve these demands. With this motivation, in this paper a unified model is derived using enhanced reinforcement learning and stochastic optimization method. Exploiting physical as well as system level network state information, our proposed dynamic network state learning model (NSLM) applies stochastic optimization to learn network state-activity that derives an optimal DPM policy and PHY switching scheduling. NSLM applies known as well as unknown network state variables to derive transmission and PHY switching policy, where it considers DPM as constrained Markov decision process (MDP) problem. Here,the use of Hidden Markov Model and Lagrangian relaxation has made NSLM convergence swift that assures delay-sensitive, QoS enriched, and bandwidth and energy efficient transmission for WMSN under uncertain network conditions. Our proposed NSLM DPM model has outperformed traditional Q-Learning based DPM in terms of buffer cost, holding cost, overflow, energy consumption and bandwidth utilization

A reliable trust-aware reinforcement learning based routing protocol for wireless medical sensor networks.

Interest in the Wireless Medical Sensor Network (WMSN) is rapidly gaining attention thanks to recent advances in semiconductors and wireless communication. However, by virtue of the sensitive medical applications and the stringent resource constraints, there is a need to develop a routing protocol to fulfill WMSN requirements in terms of delivery reliability, attack resiliency, computational overhead and energy efficiency. This doctoral research therefore aims to advance the state of the art in routing by proposing a lightweight, reliable routing protocol for WMSN. Ensuring a reliable path between the source and the destination requires making trustaware routing decisions to avoid untrustworthy paths. A lightweight and effective Trust Management System (TMS) has been developed to evaluate the trust relationship between the sensor nodes with a view to differentiating between trustworthy nodes and untrustworthy ones. Moreover, a resource-conservative Reinforcement Learning (RL) model has been proposed to reduce the computational overhead, along with two updating methods to speed up the algorithm convergence. The reward function is re-defined as a punishment, combining the proposed trust management system to defend against well-known dropping attacks. Furthermore, with a view to addressing the inborn overestimation problem in Q-learning-based routing protocols, we adopted double Q-learning to overcome the positive bias of using a single estimator. An energy model is integrated with the reward function to enhance the network lifetime and balance energy consumption across the network. The proposed energy model uses only local information to avoid the resource burdens and the security concerns of exchanging energy information. Finally, a realistic trust management testbed has been developed to overcome the limitations of using numerical analysis to evaluate proposed trust management schemes, particularly in the context of WMSN. The proposed testbed has been developed as an additional module to the NS-3 simulator to fulfill usability, generalisability, flexibility, scalability and high-performance requirements

3R: a reliable multi-agent reinforcement learning based routing protocol for wireless medical sensor networks.

Interest in the Wireless Medical Sensor Network (WMSN) is rapidly gaining attention thanks to recent advances in semiconductors and wireless communication. However, by virtue of the sensitive medical applications and the stringent resource constraints, there is a need to develop a routing protocol to fulfill WMSN requirements in terms of delivery reliability, attack resiliency, computational overhead and energy efficiency. This paper proposes 3R, a reliable multi-agent reinforcement learning routing protocol for WMSN. 3R uses a novel resource-conservative Reinforcement Learning (RL) model to reduce the computational overhead, along with two updating methods to speed up the algorithm convergence. The reward function is re-defined as a punishment, combining the proposed trust management system to defend against well-known dropping attacks. Furthermore, an energy model is integrated with the reward function to enhance the network lifetime and balance energy consumption across the network. The proposed energy model uses only local information to avoid the resource burdens and the security concerns of exchanging energy information. Experimental results prove the lightweightness, attacks resiliency and energy efficiency of 3R, making it a potential routing candidate for WMSN

Field test of multi-hop image sensing network prototype on a city-wide scale

Open Access funded by Chongqing University of Posts and Telecommuniocations Under a Creative Commons license, https://creativecommons.org/licenses/by-nc-nd/4.0/Wireless multimedia sensor network drastically stretches the horizon of traditional monitoring and surveillance systems, of which most existing research have utilised Zigbee or WiFi as the communication technology. Both technologies use ultra high frequencies (mainly 2.4 GHz) and suffer from relatively short transmission range (i.e. 100 m line-of-sight). The objective of this paper is to assess the feasibility and potential of transmitting image information using RF modules with lower frequencies (e.g. 433 MHz) in order to achieve a larger scale deployment such as a city scenario. Arduino platform is used for its low cost and simplicity. The details of hardware properties are elaborated in the article, followed by an investigation of optimum configurations for the system. Upon an initial range testing outcome of over 2000 m line-of-sight transmission distance, the prototype network has been installed in a real life city plot for further examination of performance. A range of suitable applications has been proposed along with suggestions for future research.Peer reviewe

Real-Time QoS Routing Protocols in Wireless Multimedia Sensor Networks: Study and Analysis

Many routing protocols have been proposed for wireless sensor networks. These routing protocols are almost always based on energy efficiency. However, recent advances in complementary metal-oxide semiconductor (CMOS) cameras and small microphones have led to the development of Wireless Multimedia Sensor Networks (WMSN) as a class of wireless sensor networks which pose additional challenges. The transmission of imaging and video data needs routing protocols with both energy efficiency and Quality of Service (QoS) characteristics in order to guarantee the efficient use of the sensor nodes and effective access to the collected data. Also, with integration of real time applications in Wireless Senor Networks (WSNs), the use of QoS routing protocols is not only becoming a significant topic, but is also gaining the attention of researchers. In designing an efficient QoS routing protocol, the reliability and guarantee of end-to-end delay are critical events while conserving energy. Thus, considerable research has been focused on designing energy efficient and robust QoS routing protocols. In this paper, we present a state of the art research work based on real-time QoS routing protocols for WMSNs that have already been proposed. This paper categorizes the real-time QoS routing protocols into probabilistic and deterministic protocols. In addition, both categories are classified into soft and hard real time protocols by highlighting the QoS issues including the limitations and features of each protocol. Furthermore, we have compared the performance of mobility-aware query based real-time QoS routing protocols from each category using Network Simulator-2 (NS2). This paper also focuses on the design challenges and future research directions as well as highlights the characteristics of each QoS routing protocol.https://doi.org/10.3390/s15092220

RRP: a reliable reinforcement learning based routing protocol for wireless medical sensor networks.

Wireless medical sensor networks (WMSNs) offer innovative healthcare applications that improve patients' quality of life, provide timely monitoring tools for physicians, and support national healthcare systems. However, despite these benefits, widespread adoption of WMSN advancements is still hampered by security concerns and limitations of routing protocols. Routing in WMSNs is a challenging task due to the fact that some WMSN requirements are overlooked by existing routing proposals. To overcome these challenges, this paper proposes a reliable multi-agent reinforcement learning based routing protocol (RRP). RRP is a lightweight attacks-resistant routing protocol designed to meet the unique requirements of WMSN. It uses a novel Q-learning model to reduce resource consumption combined with an effective trust management system to defend against various packet-dropping attacks. Experimental results prove the lightweightness of RRP and its robustness against blackhole, selective forwarding, sinkhole and complicated on-off attacks

An Optimized Hidden Node Handling Approach For Improving The Coverage And Network Efficiency In Wireless Multimedia Sensor Networks

Wireless Multimedia Sensor Networks (WMSNs) are comprised of sensor nodes that form the momentary network and do not rely on the support of any orthodox centralized infrastructure or administration. Such a given situation mandates that every sensor node gets the support of the other sensor nodes in order to advance the packets to the desired destination node, and specifically to the sink node. Successful transmission of online multimedia streams in wireless multimedia sensor networks (WMSNs) is a challenge due to their limited bandwidth and power resources. The existing WMSN protocols are not completely appropriate for multimedia communication. The effectiveness of WMSNs vary as it depends on the correct location of the sensor nodes in the field. Thus, maximizing the multimedia coverage is the most important issue in the delivery of multimedia contents. The nodes in WMSNs are either static or mobile. Thus, the node connections change continuously due to the mobility in wireless multimedia communication that causes an additional energy consumption and synchronization loss between neighboring nodes. The focus is on hidden node problems in WMSNs and how they can affect the network performance. Hidden nodes occur in the networks when nodes that are invisible to each other communicate with another node that is visible to these nodes at a particular period. Eventually, a collision may occur and the node will be unable to receive any packets. In addition, this study looks at the effectiveness of the optimal orientation for the sensor nodes in the environment. This work introduces an Optimized Hidden Node Handling (OHND) approach. The OHND consists of three phases: hidden node handling, message exchange, and location and view handling. These three phases aim to maximize the multimedia node coverage and improve energy efficiency, hidden node handling capacity, and packet delivery ratio. OHND helps multimedia sensor nodes to compute the directional coverage. Furthermore, an OHND is used to maintain a continuous node– continuous neighbor discovery process to handle the mobility of the nodes. To evaluate the performance of the proposed algorithms, the results are compared with other known approaches. The results demonstrate that nodes are capable of maintaining direct coverage and detecting hidden nodes in order to maximize coverage, achieve power efficiency, reduce the end-to-end delay, and improve the throughput. Finally, this study provides an efficient solution for handling the hidden node problem in case mobility

Wireless multimedia sensor networks, security and key management

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. These mentioned characteristics, challenges, and requirements of designing WMSNs open many research issues and future research directions to develop protocols, algorithms, architectures, devices, and testbeds to maximize the network lifetime while satisfying the quality of service requirements of the various applications. In this thesis dissertation, we outline the design challenges of WMSNs and we give a comprehensive discussion of the proposed architectures and protocols for the different layers of the communication protocol stack for WMSNs along with their open research issues. Also, we conduct a comparison among the existing WMSN hardware and testbeds based on their specifications and features along with complete classification based on their functionalities and capabilities. In addition, we introduce our complete classification for content security and contextual privacy in WSNs. Our focus in this field, after conducting a complete survey in WMSNs and event privacy in sensor networks, and earning the necessary knowledge of programming sensor motes such as Micaz and Stargate and running simulation using NS2, is to design suitable protocols meet the challenging requirements of WMSNs targeting especially the routing and MAC layers, secure the wirelessly exchange of data against external attacks using proper security algorithms: key management and secure routing, defend the network from internal attacks by using a light-weight intrusion detection technique, protect the contextual information from being leaked to unauthorized parties by adapting an event unobservability scheme, and evaluate the performance efficiency and energy consumption of employing the security algorithms over WMSNs

Gestion de la qualité de service et planification optimale de réseaux de capteurs multimédia sans fil

RÉSUMÉ Un RCSF est constitué d'un certain nombre d'entités (capteurs) géographiquement dispersées, de taille réduite, avec une autonomie et une puissance de traitement réduites. Ces dispositifs sont utilisés pour réaliser, de manière indépendante, des tâches comme la surveillance, le contrôle de processus industriel, etc. Les avancées en microélectronique ont conduit à l'émergence des petites caméras (type CMOS) et microphones accessibles. Ces capteurs audio-visuels peuvent être intégrés dans un RCSF pour former des RCMSF. Dans certains types d'applications, comme la surveillance des frontières, un grand nombre de ce type de capteurs est susceptible d'être déployés, sur de vastes terrains. Un volume considérable de flux audio-visuel (en plus des données) doit être transmis au centre de contrôle (le collecteur, ou SINK) pour analyse et prise de décision. Il y a donc un besoin important en termes de bande passante, avec surtout une forte contrainte en termes de délai de transmission et d'autres paramètres de RCSF. Des solutions pour le routage d'information ont été développées pour des RCSF, mais ces protocoles n'ont pas pris en compte la génération à grande échelle des données multimédia, elles sont par conséquent inadaptées aux RCMSF. Les capteurs typiquement sont omnidirectionnels, c'est-à-dire qu'ils sont capables de capter des signaux qui proviennent de toutes les directions autour d'eux. Les capteurs multimédia, en particulier les capteurs de vidéo, sont de type directionnel. Pour ce type de capteurs, l'aire de captage est limitée à un secteur donné d'un plan tridimensionnel. Malheureusement, les modèles mathématiques développés pour le placement des RCMSF conventionnels ne peuvent pas être appliqués dans le cadre de la configuration et de la planification des réseaux de capteurs directionnels. De nouveaux modèles d'optimisation sont donc nécessaires pour la capture des principaux paramètres caractérisant les capteurs directionnels. Dans cette thèse, nous abordons donc les problèmes clés suivants: le routage des données hétérogènes (scalaires et multimédia) pour les nœuds d'un RCMSF afin d'assurer une meilleure QdS aux usagers; et le déploiement optimisé de capteurs directionnels d'un RCMSF dans un espace tridimensionnel dont le but est couvrir un ensemble de points d'intérêts définis dans tel espace. Notre thèse se compose de trois articles scientifiques, chacun traitant d'une problématique bien spécifique. Le premier article traite du problème du routage d'information pour les RCMSF basé sur la QdS. Nous proposons un nouveau protocole, AntSensNet, basé sur l'heuristique de la colonie de fourmis, qui utilise plusieurs métriques de QdS pour trouver de bonnes routes pour les données multimédia et l'information scalaire. Dans la pratique, le protocole établit d'abord une structure hiérarchique sur le réseau avant de choisir les chemins appropriés pour répondre aux diverses exigences de QdS des différents types de trafic qui circulent dans le réseau. Ceci permet de maximiser l'utilisation des ressources du réseau, tout en améliorant la performance de la transmission de l'information. En outre, AntSensNet est capable d'utiliser un mécanisme efficace d'ordonnancement de paquets et de multiples chemins afin d'obtenir la distorsion minimale au moment où une application fait la transmission de la vidéo dans le réseau. Dans le deuxième article nous continuons avec le sujet de la QdS dans le RCMSFs et, plus spécifiquement, nous abordons la problématique du contrôle d'admission pour ce type de réseau. Grâce au contrôle d'admission, il est possible de déterminer si un réseau est capable de supporter un nouveau flot de données. S'il n'y a pas de contrôle d'admission dans un RCMSF, le performance du réseau sera compromis car les ressources existantes dans le réseau ne seront pas assez pour tous les flots acceptés et cela entraînera beaucoup de problèmes comme la perte de paquets des flots. Nous proposons un nouveau schéma de contrôle d'admission de nouveaux flots multimédia pour un RCMSF. Le système proposé est en mesure de déterminer si un flot de données puisse être admis dans le réseau, compte tenu de l'état actuel des liaisons de communications et l'énergie des nœuds. La décision sur l'acceptation est prise de manière distribuée, sans utiliser une entité centrale. De plus, notre schéma se présente comme un plug-in, et est adaptable à d'éventuels protocoles de routage et MAC utilisés pour la transmission de données dans les RCMSF. Nos résultats de simulation montrent l'efficacité de notre approche pour répondre aux exigences de QdS des nouveaux flots de données. Finalement, notre troisième article traite du problème du déploiement optimal des capteurs multimédia dans un espace 3D. Tel que mentionné ci-dessus, la plupart des capteurs multimédia sont du type directionnel. De surcroît, ces capteurs sont plus coûteux et plus spécialisés que les capteurs scalaires. En conséquence, les déploiements aléatoires, qui sont typiques pour les capteurs scalaires, ne sont ni souhaitables ni adéquats pour les capteurs multimédia. A cet effet, nous proposons un modèle optimal de déploiement 3D de capteurs directionnels. Ce modèle vise à déterminer le nombre minimum de capteurs directionnels connectés, leur emplacement et leur configuration, qui sont nécessaires pour couvrir un ensemble de points de contrôle dans un espace 3D donné. La configuration de chaque capteur déployé est déterminée par trois paramètres : la plage de détection, le champ de vision (FoV) et l'orientation. Nous présentons une formulation « Integer Linear Programming » (ILP) pour trouver la solution exacte du problème et aussi, un algorithme glouton capable de trouver une solution approximative (mais efficace) du problème. Nous évaluons également différentes propriétés des solutions proposées par le biais de nombreuses simulations. Avec ces trois articles on a réussi à résoudre, d'une façon à la fois innovatrice et pratique, les problèmes de routage basé sur la QdS pour les RCMSF et le déploiement de capteurs directionnels, qui sont l'objectif principal de notre recherche.----------ABSTRACT A Wireless Sensor Network (WSN) consists of a set of embedded processing units, called sensors, communicating via wireless links, whose main function is the collection of parameters related to the surrounding environment, such as temperature, pressure or the presence/motion of objects. WSN are expected to have many applications in various fields, such as industrial processes, military surveillance, observation and monitoring of habitat, etc. The availability of inexpensive hardware such as CMOS cameras and microphones that are able to ubiquitously capture multimedia content from the environment has fostered the development of Wireless Multimedia Sensor Networks (WMSNs), i.e., networks of wirelessly interconnected devices that allow retrieving video and audio streams, still images, and scalar sensor data. In addition to the ability to retrieve multimedia data, WMSNs will be able to store, process in real time, correlate and fuse multimedia data originated from heterogeneous sources, and perform actions on the environment based on the content gathered. Many applications require the sensor network paradigm to be rethought in view of the need for mechanisms to deliver multimedia content with a certain level of quality of service (QoS). Due to high bandwidth, processing and stringent Qos requirements existing solutions are not feasible for WMSNs. Since the need to minimize the energy consumption has driven most of the research in sensor networks so far, there is a need to create mechanisms to efficiently deliver application-level QoS, and to map these requirements to network-layer metrics such as latency or delay. Additionally, in WSNs, an omnidirectional sensing model is often assumed where each sensor can equally detect its environment in each direction. Instead, multimedia sensors, specially video sensor, are directional sensors. A directional sensor is characterized by its sensing region which can be viewed as a sector in a three-dimensional plane. Therefore, it can only choose one active sector (or direction) at any time instant. Unfortunately, the many methods developed for deploying traditional WSNs cannot directly be used for optimizing and configuring directional WMSNs due to the different parameters involved. Therefore, new optimization models which capture the primary parameters characterizing directional sensors are necessary. The issues aforementioned are crucial challenges for the development of WMSNs. In this thesis, we are interested in the following aspects: routing of heterogeneous data (scalar and multimedia) from the nodes of a WMSN to the sink in order to provide better QoS experience to users; and an optimized deployment of directional sensors of a WMSN in a three-dimensional surface with the objective to cover all the control points as defined in such a space. Our thesis runs through three scientific papers, each addressing a specific problem. In our first paper, we address the problem of data routing based on different QoS metrics in a WMSN. We propose a new protocol AntSensNet, based on the traditional ant-based algorithm. The AntSensNet protocol builds a hierarchical structure on the network before choosing suitable paths to meet various QoS requirements from different kinds of traffic, thus maximizing network utilization, while improving its performance. In addition, AntSensNet is able to use a efficient multipath video packet scheduling in order to get minimum video distortion transmission. In the second paper, we address the problem of connection admission control for WMSNs. With admission control, it is possible to determine whether a network is capable of supporting a new data stream. Without admission control in a WMSN, the network performance will be compromised because the existing resources within the network cannot be enough for all the flows accepted and this will cause many problems such as packet loss and congestion. Taking multiple parameters into account, we propose a novel connection admission control scheme for the multimedia traffic circulating in the network. The proposed scheme is able to determine if a new flow can be admitted in the network considering the current link states and the energy of the nodes. The decision about accepting is taken in a distributed way, without trusting in a central entity to take this decision. In addition, our scheme works like a plug-in, being easily adaptable to any routing and MAC protocols. Our simulation results show the effectiveness of our approach to satisfy QoS requirements of flows and achieve fair bandwidth utilization and low jitter. Finally, in the third paper, we address the problem of optimal deployment of directional sensors in a 3D space. We have already mentioned that conventional methods to deploy omnidirectional sensors are not suitable to deploy directional sensors. To remedy this deficiency, we propose a mathematical model which aims at to determine the minimum number of connected directional multimedia sensor nodes and their configuration, needed to cover a set of control points in a given 3D space. The configuration of each deployed sensor is determined by three parameters: sensing range, field of view and orientation. We present the exact ILP formulation for the problem and an approximate (but computationally efficient) greedy algorithm solution. We also evaluate different properties of the proposed solutions through extensive simulations. Overall, the proposed solutions in this thesis are both innovative and practical. With these three papers, we have been successfully resolved the problems of a QoS-based routing protocol for WMSN and an optimal deployment of directional sensors in a 3D space, which are the components of the main objective of this thesis