48 research outputs found

    Enhancement of The IEEE 802.15.4 Standard By Energy Efficient Cluster Scheduling

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    The IEEE 802.15.4 network is gaining popularity due to its wide range of application in Industries and day to day life. Energy Conservation in IEEE 802.15.4 nodes is always a concern for the designers as the life time of a network depends mainly on minimizing the energy consumption in the nodes. In ZigBee cluster-tree network, the existing literature does not provide combined solution for co-channel interference and power efficient scheduling. In addition, the technique that prevents network collision has not been provided. Delay and reliability issues are not addressed in the QoS-aware routing. Congestion is one of the major challenges in IEEE 802.15.4 Network. This network also has issues in admitting real time flows. The aim of the present research is to overcome the issues mentioned above by designing Energy Efficient Cluster Scheduling and Interference Mitigation, QoS Aware Inter-Cluster Routing Protocol and Adaptive Data Rate Control for Clustered Architecture for IEEE 802.15.4 Networks. To overcome the issue of Energy efficiency and network collision energy efficient cluster scheduling and interference mitigation for IEEE 802.15.4 Network is proposed. It uses a time division cluster scheduling technique that offers energy efficiency in the cluster-tree network. In addition, an interference mitigation technique is demonstrated which detects and mitigates the channel interference based on packet-error detection and repeated channel-handoff command transmission. For the issues of delay and reliability in cluster network, QoS aware intercluster routing protocol for IEEE 802.15.4 Networks is proposed. It consists of some modules like reliability module, packet classifier, hello protocol module, routing service module. Using the Packet classifier, the packets are classified into the data and hello packets. The data packets are classified based on the priority. Neighbour table is constructed to maintain the information of neighbour nodes reliabilities by Hello protocol module. Moreover, routing table is built using the routing service module. The delay in the route is controlled by delay metrics, which is a sum of queuing delay and transmission delay. For the issues of congestion and admit real-time flows an Adaptive data rate control for clustered architecture in IEEE 802.15.4 Networks is proposed. A network device is designed to regulate its data rate adaptively using the feedback message i.e. Congestion Notification Field (CNF) in beacon frame received from the receiver side. The network device controls or changes its data rate based on CNF value. Along with this scalability is considered by modifying encoding parameters using Particle Swarm Optimization (PSO) to balance the target output rate for supporting high data rate. Simulation results show that the proposed techniques significantly reduce the energy consumption by 17% and the network collision, enhance the performance, mitigate the effect of congestion, and admit real-time flows

    A Comprehensive Analysis of Literature Reported Mac and Phy Enhancements of Zigbee and its Alliances

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    Wireless communication is one of the most required technologies by the common man. The strength of this technology is rigorously progressing towards several novel directions in establishing personal wireless networks mounted over on low power consuming systems. The cutting-edge communication technologies like bluetooth, WIFI and ZigBee significantly play a prime role to cater the basic needs of any individual. ZigBee is one such evolutionary technology steadily getting its popularity in establishing personal wireless networks which is built on small and low-power digital radios. Zigbee defines the physical and MAC layers built on IEEE standard. This paper presents a comprehensive survey of literature reported MAC and PHY enhancements of ZigBee and its contemporary technologies with respect to performance, power consumption, scheduling, resource management and timing and address binding. The work also discusses on the areas of ZigBee MAC and PHY towards their design for specific applications

    The Synchronized Peer-to-Peer Framework and Distributed Contention-Free Medium Access for Multihop Wireless Sensor Networks

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    IEEE 802.15.4 is a low-power, low-rate MAC/PHY standard that meets most of the stringent requirements of singlehop wireless sensor networks. Sensor networks with nodal populations composed of thousands of devices have been envisioned in conjunction with environmental, vehicular, military applications, and many others. However, such large sensor network deployments necessitate multihop support as well as low power consumption. In the light of the standard's extremely limited joint support of the two aforementioned attributes, this paper presents two essential contributions. First, a framework is proposed to implement a new IEEE 802.15.4 operating mode, namely, the synchronized peer-to-peer mode. This mode is designed to enable the standard's low-power features in peer-to-peer multihop-ready topologies. The second contribution is a distributed GTS (dGTS) management scheme designed to function in the newly devised network mode. This protocol provides reliable contention-free access in peer-to-peer topologies in a completely distributed manner. Assuming optimal routing, our simulation experiments reveal perfect delivery ratios as long as the traffic load does not reach or surpass its saturation threshold. dGTS sustains at least twice the delivery ratio of contention-based access under suboptimal dynamic routing. Moreover, the dGTS scheme exhibits minimum power consumption by eliminating the retransmissions attributed to contention, which, in turn, reduces the number of transmissions to a minimum

    Routing algorithms for wireless sensor : networks based on the duty cycle of its components

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    [eng] Wireless sensor network is one of the most important topics in the current data transferring. In fact regarding to data gathering and transformation, cost effective is the top topic and optimum point, which every vendors and sector are focusing on it. In the field of petrochemical regarding sensitive processes could not stay out of this scope and start to monitor the gas pipes and processes over the wireless fashion. Therefore some items should have been taking into considerations such as: instant monitoring, nonstop characteristic, long term investing and energy consuming. According to those aforesaid items, we have planned to do an investigation and find the feasibly of how we can to create and distribute a network to have accuracy to measurement , sending data reliability, having long term network life cycle and having minimum energy consuming. Therefore the only technology could help us was IEEE 802.15.4 with mixed of microcontrollers and transceivers, able to manipulate to reach out our objects in maximizing lifetime and minimizing latency in wsn, as an unique routing algorithm in Mobile ad Hoc Network. WSN in fact is a relatively new section of networking technology and nowadays is more popular. The reason of these advantages instead of others is low-power microcontroller and inexpensive sensor usage for any communications and also simple sensor designing. Regarding to network layers, Physical layer for WSN based on IEEE802.15.4 is fundamental of frames and packets transactions. So two main devices which are involving in this project: transceivers such as CC2520 and CC3200 ZigBee/IEEE 802.15.4 RF, managed by microcontrollers. Common controller for those transceivers such as MSP430F1611 16-bit MSP430 family for Texas instrument in the nodes and coordinators ideas were selected. One step more close to the idea, was other layer so called Link layer or in other hand MAC layer. Another advantage of WSN is ability to manipulate MAC layer, because modifications in lower layer always has low Energy consuming than other layers. Therefore according to these circumstances, MAC protocols are able to energy efficiency, also reduce and achieve to zero based of unused time in WSN. So any WSN, energy wasting could be control in MAC sub layer and even though MAC protocols. Other layer in WSN is declared as a Network layer, the logical way which those packets could be find the best way and shortest path in minimum time as possible and reachability to the main point based on node and coordinator. Nodes are programmed in upper layer and have been matched with MAC layer, now it's time to join and stick the frames in a packet and involving to each other. Meanwhile we decided to create a middle layer through MAC and Network layer to play as a bridge, mainly called VRT (Variable Response Time) and FRT (Fixed Response Time) to control the energy consumption in the process of routing in network layer. This algorithm is cooperating with MAC layer in sleep and wake up modes, in fact with VRT, nodes just received their needs and captured the vital packet in wake up mode, sends back the answer, now the task is finished and both sided transaction is done. After that, it's not need to have more listening and capturing packets from the remote nodes as a coordinator therefore, left the transmission process to save more energy for further wireless communication stream in sleep mode. Also FRT is another algorithm in MAC layer, to decrease the energy consumption. This algorithm is switch based energy control, as a same concept in VRT in sleeping and wakeup mode. Finally we have design this algorithm in Simulator and real world. The results correlate quite well results showing as a good agreement between two worlds, also we have obtained better results in battery consumption over network life cycle to other business algorithms.[spa] En este trabajo nos focalizaremos en la minimización del consumo a partir de la minimización del número de transmisiones. Buscamos por tanto aquel algoritmo que nos permita aumentar la probabilidad de aciertos. Esta idea, diseñará el algoritmo de enrutamiento que mejor se ajusta a la red MANET. Una vez simulada la red se diseñará un "testbed" en donde una parte de la red se implementará de forma real, mediante la introducción de sensores inalámbricos y la otra parte se hará de forma simulada, a través de una interfaz que interconecta el mundo real con la simulación de Spyder. Se pretende ver que ambos mundos progresan de forma similar. Con respecto a la capa de OSI en WSN, sería prioritaria la capa física o capa de hardware, por este motivo nuestra proyecto también se centra en el tipo determinado de hardware que debe aplicarse para obtener resultados satisfactorios. Entonces tratamos las características de los dos hardwares, el transceiver y el microcontroller. También se trata en este apartado su concepto lógico de acuerdo con la ficha técnica oficial IEEE802.15.4. La segunda prioridad de la capa OSI se centra en el Medium Access Control (MAC) de la capa. En esta capa nuestro objetivo se logrará mediante la manipulación de las addresses MAC. Los protocolos MAC deben estar orientados a la reducción del consumo de energía y también a la reducción del tiempo no utilizado en WSN, para ello aplicamos algunas políticas para controlar los comportamientos del tráfico en esta capa para cambiar el consumo de energía, la vida útil de la red y evitar el gasto innecesario de recursos, en realidad concentramos a nuestro algoritmo VRT y FRT. Respecto de la idea principal, de controlar los sensores para aumentar la vida útil de la red y disminuir el consumo de energía. En realidad se explica cómo controlar la capa MAC y forzar el hardware para lograr el objetivo principal de este proyecto. De hecho podemos decir que mejoramos el reenvío de paquetes entre los sensores intermedios, buscando el promedio de distancia HOP más corta desde el origen al destino, así como la disminución del consumo de energía en cada sensor

    Radio Communications

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    In the last decades the restless evolution of information and communication technologies (ICT) brought to a deep transformation of our habits. The growth of the Internet and the advances in hardware and software implementations modified our way to communicate and to share information. In this book, an overview of the major issues faced today by researchers in the field of radio communications is given through 35 high quality chapters written by specialists working in universities and research centers all over the world. Various aspects will be deeply discussed: channel modeling, beamforming, multiple antennas, cooperative networks, opportunistic scheduling, advanced admission control, handover management, systems performance assessment, routing issues in mobility conditions, localization, web security. Advanced techniques for the radio resource management will be discussed both in single and multiple radio technologies; either in infrastructure, mesh or ad hoc networks

    A Multi-Hop 6LoWPAN Wireless Sensor Network for Waste Management Optimization

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    In the first part of this Thesis several Wireless Sensor Network technologies, including the ones based on the IEEE 802.15.4 Protocol Standard like ZigBee, 6LoWPAN and Ultra Wide Band, as well as other technologies based on other protocol standards like Z-Wave, Bluetooth and Dash7, are analyzed with respect to relevance and suitability with the Waste Management Outsmart European FP7 Project. A particular attention is given to the parameters which characterize a Large Scale WSN for Smart Cities, due to the amount of sensors involved and to the practical application requested by the project. Secondly, a prototype of sensor network is proposed: an Operative System named Contiki is chosen for its portability on different hardware platforms, its Open Source license, for the use of the 6LoW-PAN protocol and for the implementation of the new RPL routing protocol. The Operative System is described in detail, with a special focus on the uIPv6 TCP/IP stack and RPL implementation. With regard to this innovative routing proto col designed specifically for Low Power Lossy Networks, chapter 4 describes in detail how the network topology is organized as a Directed Acyclic Graph, what is an RPL Instance and how downward and upward routes are constructed and maintained. With the use of several AVR Atmel modules mounting the Contiki OS a real WSN is created and, with an Ultrasonic Sensor, the filling level of a waste basket prototype is periodically detected and transmitted through a multi-hop wireless network to a sink nodeope

    A Multi-Radio Interface for Dependable Body Area Network Communications

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    Body Area Networks (BANs) are emerging as a convenient option for patient monitoring. They have shown potential in improving health care services through a network of external or implanted biosensors and actuators collecting real-time physiological data. Advancements in wireless networking and sensor development are expediting the adoption of BANs. However, real-time patient monitoring still remains a challenge due to network failures and congestion. In order to improve channel loss resilience and thus link availability, a multi-radio systems approach is adopted incorporating Bluetooth and Wi-Fi. In this work, we propose a multi-radio interface designed for a BAN to improve end-to-end communications. A multi-radio BAN controller is introduced to interface between the two wireless protocols (Wi-Fi and Bluetooth), control inter-radio handovers, manage a shared transmission buffer, and overall, route data accordingly through the protocol stacks. Simulations are conducted to study the performance of the system by adjusting handover timing and its effect on link availability. Advancing a handover has the benefit of a higher throughput at the cost of an increase in power consumption and timing overhead. Furthermore, various human mobility models, AP placement arrangements, and network densities are simulated to evaluate the performance of the BAN multi-radio interface. Sparse networks were found to have the most gain from the addition of the secondary Bluetooth radio system, as primary AP coverage was already very limited. Simulation results for various combinations of simulation parameters are presented to illustrate the improvement in BAN dependability through a multi-radio interface

    Simulation of physical and media access control (MAC) for resilient and scalable wireless sensor networks

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    The resilience of wireless sensor networks is investigated. A key concept is that scale-free network principles can be adapted to artificially create resilient wireless sensor networks. As scale-free networks are known to be resilient to errors but vulnerable to attack, a strategy using "cold-start" diversity is proposed to reduce the vulnerability to attacks. The IEEE 802.15.4 MAC and ZigBee protocols are investigated for their ability to form resilient clusters. Our investigation reveals there exists deficiencies in these protocols and the possibility of selfdirected and attack-directed denial-of-service is significant. Through insights gained, techniques are recommended to augment the protocols, increasing their resilience without major changes to the standard itself. Since both topological and protocol resilience properties are investigated, our results reveal important insights. Simulation of the physical and media access control layers using ns-2 is carried out to validate key concepts and approach.http://archive.org/details/simulationofphys109452893Approved for public release; distribution is unlimited

    A study into prolonging Wireless Sensor Network lifetime during disaster scenarios

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    A Wireless Sensor Network (WSN) has wide potential for many applications. It can be employed for normal monitoring applications, for example, the monitoring of environmental conditions such as temperature, humidity, light intensity and pressure. A WSN is deployed in an area to sense these environmental conditions and send information about them to a sink. In certain locations, disasters such as forest fires, floods, volcanic eruptions and earth-quakes can happen in the monitoring area. During the disaster, the events being monitored have the potential to destroy the sensing devices; for example, they can be sunk in a flood, burnt in a fire, damaged in harmful chemicals, and burnt in volcano lava etc. There is an opportunity to exploit the energy of these nodes before they are totally destroyed to save the energy of the other nodes in the safe area. This can prolong WSN lifetime during the critical phase. In order to investigate this idea, this research proposes a new routing protocol called Maximise Unsafe Path (MUP) routing using Ipv6 over Low power Wireless Personal Area Networks (6LoWPAN). The routing protocol aims to exploit the energy of the nodes that are going to be destroyed soon due to the environment, by concentrating packets through these nodes. MUP adapts with the environmental conditions. This is achieved by classifying four different levels of threat based on the sensor reading information and neighbour node condition, and represents this as the node health status, which is included as one parameter in the routing decision. High priority is given to a node in an unsafe condition compared to another node in a safer condition. MUP does not allow packet routing through a node that is almost failed in order to avoid packet loss when the node fails. To avoid the energy wastage caused by selecting a route that requires a higher energy cost to deliver a packet to the sink, MUP always forwards packets through a node that has the minimum total path cost. MUP is designed as an extension of RPL, an Internet Engineering Task Force (IETF) standard routing protocol in a WSN, and is implemented in the Contiki Operating System (OS). The performance of MUP is evaluated using simulations and test-bed experiments. The results demonstrate that MUP provides a longer network lifetime during a critical phase of typically about 20\% when compared to RPL, but with a trade-off lower packet delivery ratio and end-to-end delay performances. This network lifetime improvement is crucial for the WSN to operate for as long as possible to detect and monitor the environment during a critical phase in order to save human life, minimise loss of property and save wildlife

    Filtered multi-carrier modulations for industrial wireless communications based on cognitive radio

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    Doktoretza-tesi honetako helburu nagusia, hari gabeko komunikazio industrialetarako fidagarritasun maila onargarria eman dezakeen maila fisikoko modulazio bat aurkitzea da. Eremu industrialetako radio bidezko kanaletan ematen diren komunikazioetarako baldintza bereziki aurkakoak direla eta, helburu hori lortzea benetako erronkatzat jo liteke. Gainera, modulazio horrek \Radio Cognitiva" deritzoten teknikekin bateragarria izan beharra dauka, hauek hari gabeko komunikazioen fidagarritasuna hobetzeko gaitasuna baitute. Bibliografian oinarrituz, gaur egungo baliabideekin hari gabeko komunikazio industrial kasu ugariri konponbidea emateko aukera badela ondoriozta genezake, baina ez kasu guztiei ordea. Hari gabeko kanalen egoera bereziki aurkakoa denerako eta komunikazio sistemek denbora muga bereziki zorrotzak bete behar dituztenerako, ezta erantzun nahikoa ona eman lezakeen hari gabeko komunikazio sistema industrialik bibliografia zientifikoan. Hori dela eta, doktoretza tesi honetan, \Radio Cognitiva" delakoa eta 5G-rako aurreikusita dauden filtro bankuetan oinarrituriko modulazio multigarraiatzaileak bezalako teknologia hasiberrietara jotzen dugu, aurrez aipaturiko arazoari konponbide berriak bilatu nahian. Bibliografian dauden filtro bankuetan oinarrituriko modulazio multi-garraiatzaileak aztertu eta ondoren beraien egokitasuna ebaluatzen dugu, kanal dispertsiboen aurkako sendotasuna eta \Radio Cognitiva" teknikekin izan lezaketen bateragarritasuna irizpide hartuz. Ebaluaketa horretan oinarrituz, doktoretza-tesi honetan \Radio Cognitiva" teknikekin bateragarria den WCP-COQAM proposatzen dugu modulazio industrial gisa. Modulazio teknika berau erakusteaz gain, bibliografian eskuragarri ez dauden WCP-COQAM-rentzat sinkronizazio eta kanal estimazio teknikak ere aurkezten ditugu.El objetivo principal de esta tesis doctoral consiste en encontrar una modulación de capa física capaz de proporcionar robustez y fiabilidad suficientes a sistemas de comunicaciones inalámbricas industriales. Esto supone un desafío, dadas las adversas condiciones del canal inalámbrico propias de entornos industriales. Además, dicha modulación debería presentar una alta compatibilidad con las técnicas de Radio Cognitiva, debido al potencial de éstas para mejorar la fiabilidad de las comunicaciones inalámbricas. Basándonos en la bibliografía, concluimos que las soluciones presentes en el estado del arte actual cubren una amplia variedad de escenarios dentro de las comunicaciones inalámbricas industriales, pero no todas. Para los escenarios con canales altamente dispersivos y requerimientos de tiempo especialmente estrictos, no existe ninguna solución en la industria ni dentro de la bibliografía científica. En esta tesis doctoral nos centramos en tecnologías incipientes como la Radio Cognitiva y las modulaciones multi-portadora con bancos de filtros para 5G para tratar de buscar nuevas soluciones al problema anteriormente descrito. Por lo tanto, analizamos algunas de las técnicas multi-portadora con bancos de filtros presentes en la bibliografía científica y las evaluamos basándonos en su robustez frente a canales altamente dispersivos y su compatibilidad con la Radio Cognitiva. Basándonos en dicha evaluación, proponemosWCP-COQAM como posible candidata a modulación industrial compatible con Radio Cognitiva. Además de la propia técnica de modulación, presentamos métodos de sincronización y estimación de canal para la misma que no se encuentran presentes en el estado del arte.The main goal of this doctoral thesis is to find a physical layer modulation able to provide high enough robustness and reliability levels for wireless industrial communications systems. Considering the harsh wireless channel conditions of industrial environments, that goal implies a considerable challenge. Besides, this modulation should be highly compatible with Cognitive Radio techniques, due to their potential to improve the reliability of wireless communications. Based on the bibliography, we conclude that the existent solutions in the current state of the art cover a wide range of wireless industrial communications scenarios, but not all of them. There is no solution, neither in the industry nor in the scientific bibliography, for those scenarios involving highly dispersive wireless channels and particularly stringent timeliness requirements. In this doctoral thesis, we focus on upcoming technologies such as Cognitive Radio and multi-carrier modulations based on filter banks for 5G, in order to search new solutions for the aforementioned problem. Therefore, we analyse some of the multi-carrier modulations based on filter banks of the scientific bibliography and we evaluate them in terms of robustness against highly dispersive channels and in terms of compatibility with Cognitive Radio. In this doctoral thesis we propose the modulation WCP-COQAM as possible candidate for industrial wireless modulation and compatible with Cognitive Radio. In addition to the modulation technique itself, we also introduce some synchronization and channel estimation techniques which are not present in the state of the art
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