Geographic Centroid Routing for Vehicular Networks

A number of geolocation-based Delay Tolerant Networking (DTN) routing protocols have been shown to perform well in selected simulation and mobility scenarios. However, the suitability of these mechanisms for vehicular networks utilizing widely-available inexpensive Global Positioning System (GPS) hardware has not been evaluated. We propose a novel geolocation-based routing primitive (Centroid Routing) that is resilient to the measurement errors commonly present in low-cost GPS devices. Using this notion of Centroids, we construct two novel routing protocols and evaluate their performance with respect to positional errors as well as traditional DTN routing metrics. We show that they outperform existing approaches by a significant margin.Comment: 6 page

Evaluation of Energy Consumption in Industry 4.0

Wireless sensor networks (WSN) are significantly important in the advanced monitoring of applications for the Internet of Things, particularly in difficult-to-access locations where wired solutions are impractical or expensive. Critical elements and characteristics of WSNs in terms of power consumption are being characterized and evaluated. However, there is a gap in research in terms of selecting and structuring the most efficient (WSN) in consideration of energy sustainability and the amount of required energy by the WSN that can be supplied wirelessly. In this thesis, a systems-level approach was taken to evaluate the energy required for sensing, processing, and communication over a WSN for an industrial application. A literature review was also conducted to identify the power consumption of some transducers typically used in manufacturing, such as temperature, acceleration, and displacement transducers. Additionally, the power consumption of the commonly available local processing units used to produce “smart” sensors was compared in this work. Different data transmission protocols were also evaluated for power consumption in different operation modes for different microcontrollers. These requirements and results taken from the literature were used to identify the power consumption at each location in WSN. This was then used to create a framework for surveying the theoretical requirement (limits) to power each of these locations. Various power sources were considered as possible solutions, including energy storage (wired and wireless charging), power distribution, and power harvesting techniques. The framework can be used in one of two ways; the WSN can either be modified to reduce power consumption to meet supply (for example, changing the operational mode to a more energy-efficient one), or a different power supply can be proposed to meet demand. In this way, the framework provides a tool for the design of any industry-based WSN. Finally, a machine tool was used as a case study to show how the framework can be used, in consideration of the available energy harvesting techniques that can be used to power specific elements of the WSN. Further work should focus on investigating the possibility of using other techniques to optimize the power consumption of WSNs considering the available wireless energy sources, as well as suggest other efficient techniques

An efficient multichannel wireless sensor networks MAC protocol based on IEEE 802.11 distributed co-ordinated function.

This research aimed to create new knowledge and pioneer a path in the area relating to future trends in the WSN, by resolving some of the issues at the MAC layer in Wireless Sensor Networks. This work introduced a Multi-channel Distributed Coordinated Function (MC-DCF) which takes advantage of multi-channel assignment. The backoff algorithm of the IEEE 802.11 distributed coordination function (DCF) was modified to invoke channel switching, based on threshold criteria in order to improve the overall throughput for wireless sensor networks. This work commenced by surveying different protocols: contention-based MAC protocols, transport layer protocols, cross-layered design and multichannel multi-radio assignments. A number of existing protocols were analysed, each attempting to resolve one or more problems faced by the current layers. The 802.15.4 performed very poorly at high data rate and at long range. Therefore 802.15.4 is not suitable for sensor multimedia or surveillance system with streaming data for future multichannel multi-radio systems. A survey on 802.11 DCF - which was designed mainly for wireless networks –supports and confirm that it has a power saving mechanism which is used to synchronise nodes. However it uses a random back-off mechanism that cannot provide deterministic upper bounds on channel access delay and as such cannot support real-time traffic. The weaknesses identified by surveying this protocol form the backbone of this thesis The overall aim for this thesis was to introduce multichannel with single radio as a new paradigm for IEEE 802.11 Distributed Coordinated Function (DCF) in wireless sensor networks (WSNs) that is used in a wide range of applications, from military application, environmental monitoring, medical care, smart buildings and other industry and to extend WSNs with multimedia capability which sense for instance sounds or motion, video sensor which capture video events of interest. Traditionally WSNs do not need high data rate and throughput, since events are normally captured periodically. With the paradigm shift in technology, multimedia streaming has become more demanding than data sensing applications as such the need for high data rate protocol for WSN which is an emerging technology in this area. The IEEE 802.11 can support data rates up to 54Mbps and 802.11 DCF was designed specifically for use in wireless networks. This thesis focused on designing an algorithm that applied multichannel to IEEE 802.11 DCF back-off algorithm to reduce the waiting time of a node and increase throughput when attempting to access the medium. Data collection in WSN tends to suffer from heavy congestion especially nodes nearer to the sink node. Therefore, this thesis proposes a contention based MAC protocol to address this problem from the inspiration of the 802.11 DCF backoff algorithm resulting from a comparison of IEEE 802.11 and IEEE 802.15.4 for Future Green Multichannel Multi-radio Wireless Sensor Networks

End-to-End Resilience Mechanisms for Network Transport Protocols

The universal reliance on and hence the need for resilience in network communications has been well established. Current transport protocols are designed to provide fixed mechanisms for error remediation (if any), using techniques such as ARQ, and offer little or no adaptability to underlying network conditions, or to different sets of application requirements. The ubiquitous TCP transport protocol makes too many assumptions about underlying layers to provide resilient end-to-end service in all network scenarios, especially those which include significant heterogeneity. Additionally the properties of reliability, performability, availability, dependability, and survivability are not explicitly addressed in the design, so there is no support for resilience. This dissertation presents considerations which must be taken in designing new resilience mechanisms for future transport protocols to meet service requirements in the face of various attacks and challenges. The primary mechanisms addressed include diverse end-to-end paths, and multi-mode operation for changing network conditions