171 research outputs found
QoS BASED ENERGY EFFICIENT ROUTING IN WIRELESS SENSOR NETWORK
A Wireless Sensor Networks (WSN) is composed of a large number of low-powered
sensor nodes that are randomly deployed to collect environmental data. In a WSN,
because of energy scarceness, energy efficient gathering of sensed information is one
of the most critical issues. Thus, most of the WSN routing protocols found in the
literature have considered energy awareness as a key design issue. Factors like
throughput, latency and delay are not considered as critical issues in these protocols.
However, emerging WSN applications that involve multimedia and imagining sensors
require end-to-end delay within acceptable limits. Hence, in addition to energy
efficiency, the parameters (delay, packet loss ratio, throughput and coverage) have
now become issues of primary concern. Such performance metrics are usually
referred to as the Quality of Service (QoS) in communication systems. Therefore, to
have efficient use of a sensor node’s energy, and the ability to transmit the imaging
and multimedia data in a timely manner, requires both a QoS based and energy
efficient routing protocol. In this research work, a QoS based energy efficient routing
protocol for WSN is proposed. To achieve QoS based energy efficient routing, three
protocols are proposed, namely the QoS based Energy Efficient Clustering (QoSEC)
for a WSN, the QoS based Energy Efficient Sleep/Wake Scheduling (QoSES) for a
WSN, and the QoS based Energy Efficient Mobile Sink (QoSEM) based Routing for a
Clustered WSN.
Firstly, in the QoSEC, to achieve energy efficiency and to prolong
network/coverage lifetime, some nodes with additional energy resources, termed as
super-nodes, in addition to normal capability nodes, are deployed. Multi-hierarchy
clustering is done by having super-nodes (acting as a local sink) at the top tier, cluster
head (normal node) at the middle tier, and cluster member (normal node) at the lowest
tier in the hierarchy. Clustering within normal sensor nodes is done by optimizing the
network/coverage lifetime through a cluster-head-selection algorithm and a
sleep/wake scheduling algorithm. QoSEC resolves the hot spot problem and prolongs
network/coverage lifetime.
Secondly, the QoSES addressed the delay-minimization problem in sleep/wake
scheduling for event-driven sensor networks for delay-sensitive applications. For this
purpose, QoSES assigns different sleep/wake intervals (longer wake interval) to
potential overloaded nodes, according to their varied traffic load requirement defined
a) by node position in the network, b) by node topological importance, and c) by
handling burst traffic in the proximity of the event occurrence node. Using these
heuristics, QoSES minimizes the congestion at nodes having heavy traffic loads and
ultimately reduces end-to-end delay while maximizing the throughput.
Lastly, the QoSEM addresses hot spot problem, delay minimization, and QoS
assurance. To address hot-spot problem, mobile sink is used, that move in the network
to gather data by virtue of which nodes near to the mobile sink changes with each
movement, consequently hot spot problem is minimized. To achieve delay
minimization, static sink is used in addition to the mobile sink. Delay sensitive data is
forwarded to the static sink, while the delay tolerant data is sent through the mobile
sink. For QoS assurance, incoming traffic is divided into different traffic classes and
each traffic class is assigned different priority based on their QoS requirement
(bandwidth, delay) determine by its message type and content. Furthermore, to
minimize delay in mobile sink data gathering, the mobile sink is moved throughout
the network based on the priority messages at the nodes. Using these heuristics,
QoSEM incur less end-to-end delay, is energy efficient, as well as being able to
ensure QoS.
Simulations are carried out to evaluate the performance of the proposed protocols
of QoSEC, QoSES and QoSEM, by comparing their performance with the established
contemporary protocols. Simulation results have demonstrated that when compared
with contemporary protocols, each of the proposed protocol significantly prolong the
network and coverage lifetime, as well as improve the other QoS routing parameters,
such as delay, packet loss ratio, and throughput
Contribution to the design of VANET routing protocols for realistic urban environments
One of the main concerns of the cities' administration is mobility management. In Intelligent Transportation Systems (ITS), pedestrians, vehicles and public transportation systems could share information and react to any situation in the city. The information sensed by vehicles could be useful for other vehicles and for the mobility authorities. Vehicular Ad hoc Networks (VANETs) make possible the communication between vehicles (V2I) and also between vehicles and fixed infrastructure (V2I) managed by the city's authorities. In addition, VANET routing protocols minimize the use of fixed infrastructure since they employ multi-hop V2V communication to reach reporting access points of the city.
This thesis aims to contribute in the design of VANET routing protocols to enable reporting services (e.g., vehicular traffic notifications) in urban environments. The first step to achieve this global objective has been the study of components and tools to mimic a realistic VANET scenario. Moreover, we have analyzed the impact of the realism of each one of those components in the simulation results.
Then, we have improved the Address Resolution procedure in VANETs by including it in the routing signaling messages. Our approach simplifies the VANET operation and increases the packet delivery ratio as consequence. Afterwards, we have tackled the issue of having duplicate packets in unicast communications and we have proposed routing filters to lower their presence. This way we have been able to increase the available bandwidth and reduce the average packet delay with a slight increase of the packet losses.
Besides, we have proposed a Multi-Metric Map aware routing protocol (MMMR) that incorporates four routing metrics (distance, trajectory, vehicle density and available bandwidth) to take the forwarding decisions. With the aim of increasing the number of delivered packets in MMMR, we have developed a Geographical Heuristic Routing (GHR) algorithm. GHR integrates Tabu and Simulated Annealing heuristic optimization techniques to adapt its behavior to the specific scenario characteristics. GHR is generic because it could use any geographical routing protocol to take the forwarding decisions. Additionally, we have designed an easy to implement forwarding strategy based on an extended topology information area of two hops, called 2-hops Geographical Anycast Routing (2hGAR) protocol. Results show that controlled randomness introduced by GHR improves the default operation of MMMR. On the other hand, 2hGAR presents lower delays than GHR and higher packet delivery ratio, especially in high density scenarios.
Finally, we have proposed two mixed (integer and linear) optimization models to detect the best positions in the city to locate the Road Side Units (RSUs) which are in charge of gathering all the reporting information generated by vehicles.Una de las principales preocupaciones en la administración de las ciudades es la gestión de la movilidad de sus vehÃculos, debido a los problemas de tráfico como atascos y accidentes. En los sistemas inteligentes de transporte (SIT), peatones, vehÃculos y transporte público podrán compartir información y adaptarse a cualquier situación que suceda en la ciudad. La información obtenida por los sensores de los vehÃculos puede ser útil para otros vehÃculos y para las autoridades de movilidad. Las redes ad hoc vehiculares (VANETs) hacen posible la comunicación entre los propios vehÃculos (V2V) y entre vehÃculos y la infraestructura fija de la red de la ciudad (V2I). Asimismo, los protocolos de encaminamiento para redes vehiculares minimizan el uso de infraestructura fija de red, ya que los protocolos de encaminamiento VANET emplean comunicaciones multisalto entre vehÃculos para encaminar los mensajes hasta los puntos de acceso de la red en la ciudad. El objetivo de esta tesis doctoral es contribuir en el diseño de protocolos de encaminamiento en redes ad hoc vehiculares para servicios de notificaciones (p.ej. reportes del estado del tráfico) en entornos urbanos. El primer paso para alcanzar este objetivo general ha sido el estudio de componentes y herramientas para simular un escenario realista de red ad hoc vehicular. Además, se ha analizado el impacto del nivel de realismo de cada uno de los componentes de simulación en los resultados obtenidos. Asà también, se ha propuesto un mecanismo de resolución de direcciones automático y coherente para redes VANET a través del uso de los propios mensajes de señalización de los protocolos de encaminamiento. Esta mejora simplifica la operación de una red ad hoc vehicular y como consecuencia aumenta la tasa de recepción de paquetes. A continuación, se ha abordado el problema de la aparición inesperada de paquetes de datos duplicados en una comunicación punto a punto. Para ello, se ha propuesto el filtrado de paquetes duplicados a nivel del protocolo de encaminamiento. Esto ha producido un incremento del ancho disponible en el canal y una reducción del retardo medio en la trasmisión de un paquete, a costa de un mÃnimo aumento de la pérdida de paquetes. Por otra parte, hemos propuesto un protocolo de encaminamiento multi-métrica MMMR (Multi-Metric Map-aware Routing protocol), el cual incorpora cuatro métricas (distancia al destino, trayectoria, densidad de vehÃculos y ancho de banda) en las decisiones de encaminamiento. Con el objetivo de aumentar la tasa de entrega de paquetes en MMMR, hemos desarrollado un algoritmo heurÃstico de encaminamiento geográfico denominado GHR (Geographical Heuristic Routing). Esta propuesta integra las técnicas de optimización Tabu y Simulated Annealing, que permiten a GHR adaptarse a las caracterÃsticas especÃficas del escenario. Adicionalmente, hemos propuesto 2hGAR (2-hops Geographical Anycast Routing), un protocolo de encaminamiento anycast que emplea información de la topologÃa de red a dos saltos de distancia para tomar la decisión de encaminamiento de los mensajes. Los resultados muestran que la aleatoriedad controlada de GHR en su operación mejora el rendimiento de MMMR. Asimismo, 2hGAR presenta retardos de paquete menores a los obtenidos por GHR y una mayor tasa de paquetes entregados, especialmente en escenarios con alta densidad de vehÃculos. Finalmente, se han propuesto dos modelos de optimización mixtos (enteros y lineales) para detectar los mejores lugares de la ciudad donde ubicar los puntos de acceso de la red, los cuales se encargan de recolectar los reportes generados por los vehÃculos.Postprint (published version
Technology-related disasters:a survey towards disaster-resilient software defined networks
Resilience against disaster scenarios is essential to network operators, not only because of the potential economic impact of a disaster but also because communication networks form the basis of crisis management. COST RECODIS aims at studying measures, rules, techniques and prediction mechanisms for different disaster scenarios. This paper gives an overview of different solutions in the context of technology-related disasters. After a general overview, the paper focuses on resilient Software Defined Networks
A Survey on the Application of Evolutionary Algorithms for Mobile Multihop Ad Hoc Network Optimization Problems
Evolutionary algorithms are metaheuristic algorithms that provide quasioptimal solutions in a reasonable time. They have been
applied to many optimization problems in a high number of scientific areas. In this survey paper, we focus on the application of
evolutionary algorithms to solve optimization problems related to a type of complex network likemobilemultihop ad hoc networks.
Since its origin, mobile multihop ad hoc network has evolved causing new types of multihop networks to appear such as vehicular
ad hoc networks and delay tolerant networks, leading to the solution of new issues and optimization problems. In this survey, we
review the main work presented for each type of mobile multihop ad hoc network and we also present some innovative ideas and
open challenges to guide further research in this topic
QoS BASED ENERGY EFFICIENT ROUTING IN WIRELESS SENSOR NETWORK
A Wireless Sensor Networks (WSN) is composed of a large number of low-powered
sensor nodes that are randomly deployed to collect environmental data. In a WSN,
because of energy scarceness, energy efficient gathering of sensed information is one
of the most critical issues. Thus, most of the WSN routing protocols found in the
literature have considered energy awareness as a key design issue. Factors like
throughput, latency and delay are not considered as critical issues in these protocols.
However, emerging WSN applications that involve multimedia and imagining sensors
require end-to-end delay within acceptable limits. Hence, in addition to energy
efficiency, the parameters (delay, packet loss ratio, throughput and coverage) have
now become issues of primary concern. Such performance metrics are usually
referred to as the Quality of Service (QoS) in communication systems. Therefore, to
have efficient use of a sensor node’s energy, and the ability to transmit the imaging
and multimedia data in a timely manner, requires both a QoS based and energy
efficient routing protocol. In this research work, a QoS based energy efficient routing
protocol for WSN is proposed. To achieve QoS based energy efficient routing, three
protocols are proposed, namely the QoS based Energy Efficient Clustering (QoSEC)
for a WSN, the QoS based Energy Efficient Sleep/Wake Scheduling (QoSES) for a
WSN, and the QoS based Energy Efficient Mobile Sink (QoSEM) based Routing for a
Clustered WSN.
Firstly, in the QoSEC, to achieve energy efficiency and to prolong
network/coverage lifetime, some nodes with additional energy resources, termed as
super-nodes, in addition to normal capability nodes, are deployed. Multi-hierarchy
clustering is done by having super-nodes (acting as a local sink) at the top tier, cluster
head (normal node) at the middle tier, and cluster member (normal node) at the lowest
tier in the hierarchy. Clustering within normal sensor nodes is done by optimizing the
network/coverage lifetime through a cluster-head-selection algorithm and a
sleep/wake scheduling algorithm. QoSEC resolves the hot spot problem and prolongs
network/coverage lifetime.
Secondly, the QoSES addressed the delay-minimization problem in sleep/wake
scheduling for event-driven sensor networks for delay-sensitive applications. For this
purpose, QoSES assigns different sleep/wake intervals (longer wake interval) to
potential overloaded nodes, according to their varied traffic load requirement defined
a) by node position in the network, b) by node topological importance, and c) by
handling burst traffic in the proximity of the event occurrence node. Using these
heuristics, QoSES minimizes the congestion at nodes having heavy traffic loads and
ultimately reduces end-to-end delay while maximizing the throughput.
Lastly, the QoSEM addresses hot spot problem, delay minimization, and QoS
assurance. To address hot-spot problem, mobile sink is used, that move in the network
to gather data by virtue of which nodes near to the mobile sink changes with each
movement, consequently hot spot problem is minimized. To achieve delay
minimization, static sink is used in addition to the mobile sink. Delay sensitive data is
forwarded to the static sink, while the delay tolerant data is sent through the mobile
sink. For QoS assurance, incoming traffic is divided into different traffic classes and
each traffic class is assigned different priority based on their QoS requirement
(bandwidth, delay) determine by its message type and content. Furthermore, to
minimize delay in mobile sink data gathering, the mobile sink is moved throughout
the network based on the priority messages at the nodes. Using these heuristics,
QoSEM incur less end-to-end delay, is energy efficient, as well as being able to
ensure QoS.
Simulations are carried out to evaluate the performance of the proposed protocols
of QoSEC, QoSES and QoSEM, by comparing their performance with the established
contemporary protocols. Simulation results have demonstrated that when compared
with contemporary protocols, each of the proposed protocol significantly prolong the
network and coverage lifetime, as well as improve the other QoS routing parameters,
such as delay, packet loss ratio, and throughput
Crux: Locality-Preserving Distributed Services
Distributed systems achieve scalability by distributing load across many
machines, but wide-area deployments can introduce worst-case response latencies
proportional to the network's diameter. Crux is a general framework to build
locality-preserving distributed systems, by transforming an existing scalable
distributed algorithm A into a new locality-preserving algorithm ALP, which
guarantees for any two clients u and v interacting via ALP that their
interactions exhibit worst-case response latencies proportional to the network
latency between u and v. Crux builds on compact-routing theory, but generalizes
these techniques beyond routing applications. Crux provides weak and strong
consistency flavors, and shows latency improvements for localized interactions
in both cases, specifically up to several orders of magnitude for
weakly-consistent Crux (from roughly 900ms to 1ms). We deployed on PlanetLab
locality-preserving versions of a Memcached distributed cache, a Bamboo
distributed hash table, and a Redis publish/subscribe. Our results indicate
that Crux is effective and applicable to a variety of existing distributed
algorithms.Comment: 11 figure
Energy Harvesting based Mobile Cloud Network in Latency and QoS Improvement using 5G Systems by Energy Routing Optimization
D2D communication technology enables the User Equipment (UE) in 5G networks to instantly connect with other UEs, with or without partial infrastructure involvement. In a Cloud Assisted energy harvesting system, it has improved user numbers and data transmission between mobile nodes. This research propose energy harvesting for mobile cloud computing in enhancing the QoS and latency of the network. The main aim of this research is to enhance energy optimization using discrete energy efficient offloading algorithm. The routing has been optimized using fuzzy logic cognitive Bellman-Ford routing algorithm. To identify the failing node and find an alternative node to deliver the seamless services, an unique weight-based approach has been presented. The method relies on two working node parameters: execution time and failure rate. Threshold values are specified for the parameters of the chosen master node. By contrasting the values with the threshold values, the alternative node is chosen. The experimental results shows comparative analysis in terms of throughput of 96%, QoS of 96%, latency of 28%, energy consumption of 51%, end-end delay of 41%, average power consumption of 41% and PDR of 85
Towards Disruption Tolerant ICN
Information-Centric Networking (ICN) is a promi- nent topic in current
networking research. ICN design signifi- cantly considers the increased demand
of scalable and efficient content distribution for Future Internet. However,
intermittently connected mobile environments or disruptive networks present a
significant challenge to ICN deployment. In this context, delay tolerant
networking (DTN) architecture is an initiative that effec- tively deals with
network disruptions. Among all ICN proposals, Content Centric Networking (CCN)
is gaining more and more interest for its architectural design, but still has
the limitation in highly disruptive environment. In this paper, we design a
protocol stack referred as CCNDTN which integrates DTN architecture in the
native CCN to deal with network disruption. We also present the implementation
details of the proposed CCNDTN. We extend CCN routing strategies by integrating
Bundle protocol of DTN architecture. The integration of CCN and DTN enriches
the connectivity options of CCN architecture in fragmented networks.
Furthermore, CCNDTN can be beneficial through the simultaneous use of all
available connectivities and opportunistic networking of DTN for the
dissemination of larger data items. This paper also highlights the potential
use cases of CCNDTN architecture and crucial questions about integrating CCN
and DTNComment: ISCC 201
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