Kablosuz sensör ağlarinda yönlü antenlerle enerji̇ veri̇mli̇ yönlendi̇rme

Without measurements, sustainable development effort can not progress in the right direction. Wireless sensor networks are vital for monitoring in real time and making accurate measurements for such an endeavor. However small energy storage in the sensors can become a bottleneck if the wireless sensor network is not optimized at the hardware and software level. Directional antennas are such optimization technologies at the hardware level. They have advantages over the omnidirectional antennas, such as high gain, less interference, longer transmission range, and less power consumption. In wireless sensor networks, most of the energy is consumed for communication. Considering the limited energy in small scale batteries of the sensors, energy efficient (aware) routing, is one of the most important software optimization techniques. The main goal of the technique is to improve the lifetime of the wireless sensor networks. In the light of these observations, it is desirable to do a coupled design of directional antennas with network software, for fully exploiting the advantages offered by directional antenna technology. In this thesis, the possibilities of doing such integrated design are surveyed and improvements are suggested. The design of the proposed microstrip patch antenna array is discussed and the performance characteristics are assessed through simulations. In the benchmarks, the proposed routing method showed improvements in energy usage compared to the existing approaches.Ölçümler olmadan sürdürülebilir kalkınma çabaları doğru yönde ilerleyemez. Bu tür çabalar için, kablosuz sensör ağları, gerçek zamanlı olarak izleme ve kesin ölçümler yapmak için vazgeçilemez unsurdur. Ancak, sensör ağı, donanım ve yazılım düzeylerinde optimize edilmemişse, sensörlerde enerji yetersizliği görülebilinir. Yönlü antenler, donanım düzeyinde uygulanan optimizasyon teknolojilerinden biri olmakla birlikte, çok yönlü antenlerden farklı olarak, yüksek kazanç, daha az parazit, daha uzun iletim mesafesi ve daha az güç tüketimi sağlarlar. Kablosuz sensör ağlarında enerjinin çoğu iletişim için tüketilir. Sensörlerdeki limitli enerjili küçük ölçekli piller göz önüne alındığında, yazılım düzeyindeki önemli metodlardan biri olan enerji verimli (duyarlı) yönlendirme protokolü, kablosuz sensör ağının genel enerji kullanımını optimize etmek ve ömrünü uzatmak için gereklidir. Bu gözlemlerin ışığında, yönlü anten teknolojisinin sunduğu potansiyel avantajlardan tam olarak yararlanmak için, yönlü antenlerin ağ yazılımıyla birlikte entegre tasarımını yapmak arzu edilir. Bu tezde, böyle bir entegre tasarımın yapılma olasılıkları araştırılmış ve iyileştirmeler önerilmiştir. Tezde, küçük şeritli yamalı anten dizisinin tasarımı tartışılmış ve performans karakteristikleri simulasyonlarla ölçülmüştür. Önerilen yönlendirme algoritması, diğer yönlendirme algoritmaları ile karşılaştırıldığında, enerji kullanımında iyileştirmeler göstermiştirM.S. - Master of Scienc

Localization Enhanced Mobile Networks

The interest in mobile ad-hoc networks (MANETs) and often more precisely vehicular ad-hoc networks (VANETs) is steadily growing with many new applications, and even anticipated support in the emerging 5G networks. Particularly in outdoor scenarios, there are different mechanisms to make the mobile nodes aware of their geographical location at all times. The location information can be utilized at different layers of the protocol stack to enhance communication services in the network. Specifically, geographical routing can facilitate route management with smaller overhead than the traditional proactive and reactive routing protocols. In order to achieve similar advantages for radio resource management (RRM) and multiple access protocols, the concept of virtual cells is devised to exploit fully distributed knowledge of node locations. The virtual cells define clusters of MANET nodes assuming a predefined set of geographically distributed anchor points. It enables fast response of the network to changes in the nodes spatial configuration. More importantly, the notion of geographical location can be generalized to other shared contexts which can be learned or otherwise acquired by the network nodes. The strategy of enhancing communication services by shared contexts is likely to be one of the key features in the beyond-5G networks

Joint relay selection and bandwidth allocation for cooperative relay network

Cooperative communication that exploits multiple relay links offers significant performance improvement in terms of coverage and capacity for mobile data subscribers in hierarchical cellular network. Since cooperative communication utilizes multiple relay links, complexity of the network is increased due to the needs for efficient resource allocation. Besides, usage of multiple relay links leads to Inter- Cell Interference (ICI). The main objective of this thesis is to develop efficient resource allocation scheme minimizes the effect of ICI in cooperative relay network. The work proposed a joint relay selection and bandwidth allocation in cooperative relay network that ensures high achievable data rate with high user satisfaction and low outage percentage. Two types of network models are considered: single cell network and multicell network. Joint Relay Selection and Bandwidth Allocation with Spatial Reuse (JReSBA_SR) and Optimized JReSBA_SR (O_JReSBA_SR) are developed for single cell network. JReSBA_SR considers link quality and user demand for resource allocation, and is equipped with spatial reuse to support higher network load. O_JReSBA_SR is an enhancement of JReSBA_SR with decision strategy based on Markov optimization. In multicell network, JReSBA with Interference Mitigation (JReSBA_IM) and Optimized JReSBA_IM (O_JReSBA_IM) are developed. JReSBA_IM deploys sectored-Fractional Frequency Reuse (sectored- FFR) partitioning concept in order to minimize the effect of ICI between adjacent cells. The performance is evaluated in terms of cell achievable rate, Outage Percentage (OP) and Satisfaction Index (SI). The result for single cell network shows that JReSBA_SR has notably improved the cell achievable rate by 35.0%, with reduced OP by 17.7% compared to non-joint scheme at the expense of slight increase in complexity at Relay Node (RN). O_JReSBA_SR has further improved the cell achievable rate by 13.9% while maintaining the outage performance with reduced complexity compared to JReSBA_SR due to the effect of optimization. The result for multicell network shows that JReSBA_IM enhances the cell achievable rate up to 65.1% and reduces OP by 35.0% as compared to benchmark scheme. Similarly, O_JReSBA_IM has significantly reduced the RN complexity of JReSBA_IM scheme, improved the cell achievable rate up to 9.3% and reduced OP by 1.3%. The proposed joint resource allocation has significantly enhanced the network performance through spatial frequency reuse, efficient, fair and optimized resource allocation. The proposed resource allocation is adaptable to variation of network load and can be used in any multihop cellular network such as Long Term Evolution-Advanced (LTE-A) network

Routing in heterogeneous wireless ad hoc networks

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2008.Includes bibliographical references (p. 135-146).Wireless ad hoc networks are used in several applications ranging from infrastructure monitoring to providing Internet connectivity to remote locations. A common assumption about these networks is that the devices that form the network are homogeneous in their capabilities. However in reality, the networks can be heterogeneous in the capabilities of the devices. The main contribution of this thesis is the identification of issues for efficient communication in heterogeneous networks and the proposed solutions to these issues. The first part of the thesis deals with the issues of unambiguous classification of devices and device identification in ad hoc networks. A taxonomical approach is developed, which allows devices with wide range of capabilities to be classified on the basis of their functionality. Once classified, devices are characterized on the basis of different attributes. An IPv6 identification scheme and two routing services based on this scheme that allow object-object communication are developed. The identification scheme is extended to a multi-addressing scheme for wireless ad hoc networks. These two issues and the developed solutions are applicable to a broad range of heterogeneous networks. The second part of the thesis deals with heterogeneous networks consisting of omnidirectional and directional antennas. A new MAC protocol for directional antennas, request-to-pause-directional-MAC (RTP-DMAC) protocol is developed that solves the deafness issue, which is common in networks with directional antennas. Three new routing metrics, which are extensions to the expected number of transmissions (ETX) metric are developed. The first metric, ETX1, reduces the route length by increasing the transmission power. The routing and MAC layers assume the presence of bidirectional links for their proper operation. However networks with omnidirectional and directional antennas have unidirectional links. The other two metrics, unidirectional-ETX (U-ETX) and unidirectional-ETX1 (U-ETX1), increase the transmission power of the directional nodes so that the unidirectional links appear as bidirectional links at the MAC and the routing layers. The performance of these metrics in different scenarios is evaluated.by Sivaram M.S.L. Cheekiralla.Ph.D

Energy-efficient cooperative resource allocation for OFDMA

Energy is increasingly becoming an exclusive commodity in next generation wireless communication systems, where even in legacy systems, the mobile operators operational expenditure is largely attributed to the energy bill. However, as the amount of mobile traffic is expected to double over the next decade as we enter the Next Generation communications era, the need to address energy efficient protocols will be a priority. Therefore, we will need to revisit the design of the mobile network in order to adopt a proactive stance towards reducing the energy consumption of the network. Future emerging communication paradigms will evolve towards Next Generation mobile networks, that will not only consider a new air interface for high broadband connectivity, but will also integrate legacy communications (LTE/LTE-A, IEEE 802.11x, among others) networks to provide a ubiquitous communication platform, and one that can host a multitude of rich services and applications. In this context, one can say that the radio access network will predominantly be OFDMA based, providing the impetus for further research studies on how this technology can be further optimized towards energy efficiency. In fact, advanced approaches towards both energy and spectral efficient design will still dominate the research agenda. Taking a step towards this direction, LTE/LTE-A (Long Term Evolution-Advanced) have already investigated cooperative paradigms such as SON (self-Organizing Networks), Network Sharing, and CoMP (Coordinated Multipoint) transmission. Although these technologies have provided promising results, some are still in their infancy and lack an interdisciplinary design approach limiting their potential gain. In this thesis, we aim to advance these future emerging paradigms from a resource allocation perspective on two accounts. In the first scenario, we address the challenge of load balancing (LB) in OFDMA networks, that is employed to redistribute the traffic load in the network to effectively use spectral resources throughout the day. We aim to reengineer the load-balancing (LB) approach through interdisciplinary design to develop an integrated energy efficient solution based on SON and network sharing, what we refer to as SO-LB (Self-Organizing Load balancing). Obtained simulation results show that by employing SO-LB algorithm in a shared network, it is possible to achieve up to 15-20% savings in energy consumption when compared to LTE-A non-shared networks. The second approach considers CoMP transmission, that is currently used to enhance cell coverage and capacity at cell edge. Legacy approaches mainly consider fundamental scheduling policies towards assigning users for CoMP transmission. We build on these scheduling approaches towards a cross-layer design that provide enhanced resource utilization, fairness, and energy saving whilst maintaining low complexity, in particular for broadband applications

Aspects of Critical Communications in Disturbance Scenarios

Infrastructures are the foundations of modern societies. The most important ones are the so-called critical infrastructures: mobile networks and electricity networks. If these networks are damaged or otherwise unavailable, the functionality of the whole society is at risk and can result even in public safety hazards. Furthermore, people expect all the time ubiquitous access to internet through mobile networks as many services rely on these wireless networks. The dependence is growing all the time as the number of worldwide subscriptions has already exceeded the world population and the amount of internet of things (IoT) and other connected devices continues to increase exponentially.This thesis focuses on the critical communications aspects of mobile networks during disturbance scenarios. These are defined as situations where, e.g. there is a power blackout in the electricity network, which affects the functionality of the mobile network.The contributions of this thesis can be divided into three main themes. The first one is the actual functionality of mobile networks during disturbance scenarios. This includes finding out how the behavior of subscribers changes when there is an uncommon disturbance scenario in the mobile network and how to prolong the disturbance time functionality of the existing networks. The results show that subscribers utilize mobile networks more than usual already before the power blackout starts when they try to find out information about the status of an upcoming storm. Immediately after the disturbance scenario starts, the subscribers within the blackout area are more active as the statistics show 73 % increase in the number of new calls and 84 % in the amount of short message service (SMS) messages. The results show also that the majority of mobile network availability is lost after 3–4 hours from the start of the incident. In order to prolong this availability time, simulations are performed to find out how utilizing only a portion of the available base station (BS) sites affects the service coverage. The results show that around 20 % of BS sites would be enough to cover 75 % of the original service coverage. Therefore, the operational time of the so-called mobile network backup coverage could be increased several times given that core network (CN) and backhaul network are also operational.The second main theme in this thesis presents a new developed situation awareness system (SAS) that combines the outage information of both mobile and electricity networks. This is an important tool for monitoring the networks and performing disaster and disturbance management. The user interface of the developed SAS is a map view showing the outage information, i.e. the faults, in both networks. It utilizes operational data from both networks such as the coverage outage areas of the mobile network and the outages of transformers in the electricity network in near real-time. The developed SAS helps to prioritize maintenance and repair work to the most critical areas as well as help to form a better overall situation awareness that fire and rescue services and authorities could utilize for improving public safety actions.The last main theme in the thesis considers innovative solutions in order to find out methods to improve the performance, i.e., to mitigate the outage of mobile networks in disturbance scenarios. The three different approaches presented are the indirect guidance of subscribers, the concept of a temporary low altitude platform (LAP) network with the help of drones, and the concept of a macro sensor network (MSN). First, the energy and capacity aspects of mobile networks can be improved when the subscribers are indirectly guided to self-optimize their location in the serving cell area. This can result in serving more user equipment (UEs) within a cell or to decrease the amount of energy needed for transmissions. Next, the coverage aspects of a LAP system are studied in order to find out the suitability of forming a temporary emergency coverage with a wireless local area network (WLAN) equipped drones. The results show that this kind of approach could provide a suitable emergency coverage for a limited area with a reasonable number of drones. Finally, a framework for MSN is studied to investigate the possibility of bringing wireless sensor network (WSN) functionalities into mobile networks. The results show that the concept of MSN could remarkably improve the resilience of mobile networks in situations where the backhaul connection is broken. However, implementing and further developing this kind of functionality will require changes in the 3rd Generation Partnership Project (3GPP) specifications and self-organizing network (SON) features within the network.Overall, this thesis provides insight on how to develop the current and future mobile networks toward more resilient infrastructures. It highlights the importance of critical communications as a fundamental part of modern societies. Thus, securing the functionality and performance of mobile networks in all situations is crucial. As a result, the contributions in this thesis can be utilized as a starting point in the future research to develop new functionalities for mobile networks. One of such approaches can be a safety mode, which would improve the mobile network resiliency during disasters and disturbance scenarios

Analysis of the energy latency trade-off in wireless sensor networks

Wireless Sensor Networks (WSNs) haben im letzten Jahrzehnt eine erhebliche Aufmerksamkeit erlangt. Diese Netzwerke zeichnen sich durch begrenzte Energieressourcen der Sensorknoten aus. Daher ist Energieeffizienz ein wichtiges Thema in Systemdesign und -betrieb von WSNs. Diese Arbeit konzentriert sich auf großflächige Anwendungen von WSNs wie Umwelt- oder Lebensraumüberwachung, die in der Regel den Ad-hoc-Einsatz von Knoten in großen Anzahl erfordern. Ad-hoc-Einsatz und Budgetbeschränkungen hindern Entwickler an der Programmierung der Knoten mit zusätzlichen Informationen wie beispielsweise Routingtabellen, Positionskoordinaten, oder Netzwerkgrenzen. Um diese Informationen zu beschaffen, ist es üblich verschiedene Initialisierungsschemen mit erheblichen Auswirkungen auf den Energieverbrauch und den Programmieraufwand zu implementieren. In Anbetracht dieser Beschränkungen ist ein neues Paradigma für die Initialisierung und den Betrieb von WSNs notwendig, das sich durch einfachen Einsatz und minimalen Energieaufwand auszeichnet. In dieser Arbeit nutzen wir Sink-Mobilität, um den Initialisierungsoverhead und den operativen Overhead zu reduzieren. Unser erster großer Beitrag ist ein Boundary Identification Schema für WSNs mit dem Namen "Mobile Sink based Boundary Detection" (MoSBoD). Es nutzt die Sink-Mobilität um den Kommunikationsoverhead der Sensorknoten zu reduzieren, was zu einer Erhöhung der Laufzeit des WSN führt. Außerdem entstehen durch das Schema keine Einschränkungen in Bezug auf Nodeplacement, Kommunikationsmodell, oder Ortsinformationen der Knoten. Der zweite große Beitrag ist das Congestion avoidance low Latency and Energy efficient (CaLEe) Routingprotokoll für WSNs. CaLEe basiert auf der virtuellen Partitionierung eines Sensorsbereich in Sektoren und der diskreten Mobilität der Sink im WSN. Unsere Simulationsergebnisse zeigen, dass CaLEe, im Vergleich zum derzeitigen State-of-the-art, nicht nur eine erhebliche Reduzierung der durchschnittlichen Energy Dissipation per Node erzielt, sondern auch eine geringere durchschnittliche End-to-End Data Latency in realistischen Szenarien erreicht. Darüber hinaus haben wir festgestellt, dass kein einziges Protokoll in der Lage ist, eine Best-Case-Lösung (minimale Data Latency und minimale Energy Dissipation) für variierende Netzwerkkonfigurationen, die beispielsweise mithilfe der Parameter Kommunikationsbereich der Nodes, Nodedichte, Durchsatz des Sensorfelds definiert werden können, bieten. Daher ist der dritte Hauptbeitrag dieser Arbeit die Identifikation von (auf unterschiedlichen Netzwerkkonfigurationen basierenden) „Operational Regions“, in denen einzelne Protokolle besser arbeiten als andere. Zusammenfassend kann man sagen, dass diese Dissertation das klassische Energieeffizienzproblem der WSNs (Ressource-begrenzte Knoten) aufgreift und gleichzeitig die End-to-End Data Latency auf einen annehmbaren Rahmen eingrenzt.Wireless Sensor Networks (WSN) have gained a considerable attention over the last decade. These networks are characterized by limited amount of energy supply at sensor node. Hence, energy efficiency is an important issue in system design and operation of WSN. This thesis focuses on large-scale applications of WSN, such as environment or habitat monitoring that usually requires ad-hoc deployment of the nodes in large numbers. Ad-hoc deployment and budget constraints restrict developers from programming the nodes with information like routing tables, position coordinates of the node, boundary of the network. In order to acquire this information, state-of-the-art is to program nodes with various initialization schemes that are heavy both from WSN’s (energy consumption) and programmer’s perspectives (programming effort). In view of these particular constraints, we require a new paradigm for WSN initialization and operation, which should be easy to deploy and have minimal energy demands. In this thesis, we exploit sink mobility to reduce the WSN initialization and operational overhead. Our first major contribution is a boundary identification scheme for WSN, named “Mobile Sink based Boundary detection” (MoSBoD). It exploits the sink mobility to remove the communication overhead from the sensor nodes, which leads to an increase in the lifetime of the WSN. Furthermore, it does not impose any restrictions on node placement, communication model, or location information of the nodes. The second major contribution is Congestion avoidance low Latency and Energy efficient (CaLEe) routing protocol for WSN. CaLEe is based on virtual partitioning of a sensor field into sectors and discrete mobility of the sink in the WSN. Our simulation results showed that CaLEe not only achieve considerable reduction in average energy dissipation per node compared to current state-of-the-art routing protocols but also accomplish lesser average end-to-end data latency under realistic scenarios. Furthermore, we observe that no single protocol is capable of providing best-case solution (minium data latency and minimum energy dissipation) under varying network configurations, which can be defined using communication range of the nodes, node density, throughput of the sensor field etc. Therefore, the third major contribution of this thesis is the identification of operational regions (based on varying network configurations) where one protocol performs better than the other. In summary, this thesis revisits the classic energy efficiency problem of a WSN (that have resource-limited nodes) while keeping end-to-end data latency under acceptable bounds

Smart Metering Technology and Services

Global energy context has become more and more complex in the last decades; the raising prices of fuels together with economic crisis, new international environmental and energy policies that are forcing companies. Nowadays, as we approach the problem of global warming and climate changes, smart metering technology has an effective use and is crucial for reaching the 2020 energy efficiency and renewable energy targets as a future for smart grids. The environmental targets are modifying the shape of the electricity sectors in the next century. The smart technologies and demand side management are the key features of the future of the electricity sectors. The target challenges are coupling the innovative smart metering services with the smart meters technologies, and the consumers' behaviour should interact with new technologies and polices. The book looks for the future of the electricity demand and the challenges posed by climate changes by using the smart meters technologies and smart meters services. The book is written by leaders from academia and industry experts who are handling the smart meters technologies, infrastructure, protocols, economics, policies and regulations. It provides a promising aspect of the future of the electricity demand. This book is intended for academics and engineers who are working in universities, research institutes, utilities and industry sectors wishing to enhance their idea and get new information about the smart meters