Hybrid Satellite-Terrestrial Communication Networks for the Maritime Internet of Things: Key Technologies, Opportunities, and Challenges

With the rapid development of marine activities, there has been an increasing number of maritime mobile terminals, as well as a growing demand for high-speed and ultra-reliable maritime communications to keep them connected. Traditionally, the maritime Internet of Things (IoT) is enabled by maritime satellites. However, satellites are seriously restricted by their high latency and relatively low data rate. As an alternative, shore & island-based base stations (BSs) can be built to extend the coverage of terrestrial networks using fourth-generation (4G), fifth-generation (5G), and beyond 5G services. Unmanned aerial vehicles can also be exploited to serve as aerial maritime BSs. Despite of all these approaches, there are still open issues for an efficient maritime communication network (MCN). For example, due to the complicated electromagnetic propagation environment, the limited geometrically available BS sites, and rigorous service demands from mission-critical applications, conventional communication and networking theories and methods should be tailored for maritime scenarios. Towards this end, we provide a survey on the demand for maritime communications, the state-of-the-art MCNs, and key technologies for enhancing transmission efficiency, extending network coverage, and provisioning maritime-specific services. Future challenges in developing an environment-aware, service-driven, and integrated satellite-air-ground MCN to be smart enough to utilize external auxiliary information, e.g., sea state and atmosphere conditions, are also discussed

Performance analysis of wireless mesh networks for underground mines

Abstract: Underground mines are harsh environments that have unique challenges that limit wireless communication. To ensure the safety and efficiency of mining operations, communication systems play a vital role. Despite the major developments in communication technologies, underground mines are still challenging environments for wireless communication, however, the advent of wireless mesh networks offers a cutting-edge solution to the mining industry and understanding the performance of this technology is fundamental to its application in dynamic areas of underground mines. This research project aims at conducting a performance analysis of wireless mesh networks by developing a prototype system set up of wireless mesh transceivers to conduct a feasibility study of data transmission on the network in underground mines. The second aspect of this study investigates network parameters, such as latency, throughput, and signal-to-noise, as a function of increasing mesh nodes on the network and internode spacing of mesh nodes. By combining theoretical models with real-time performance of the mesh system, realistic conclusions and better recommendations can be given to mining companies with regards to deploying wireless mesh systems in their underground mines.M.Ing. (Electrical and Electronic Engineering Science

Optically Transparent Antennas and Filters for Smart City Communication

Incremental usage of mobile devices demand a new generation of wireless networks (5G) to provide faster data rates, more reliable coverage, monitor city infrastructure usage, and increase network capacity. The frequencies proposed for the upcoming 5G network would result in shorter broadcast distances and network dead zones, countered by incorporating transparent antennas into glass high rises. Transparent antennas possess, however a major challenge: low gain. This lower gain can be countered by means of employing antennas in an antenna array, boosting the gain and even giving the array the ability to beam form for the upcoming 5G network. The 5G dead zones can be countered with strategically placed transparent reflectors embedded into the glass surfaces of city high-rises. This dissertation shows there are significant effects due to the transparent antennas’ carrier concentration and film thickness. Changes in film conductivity and thicknesses results in shifts for filter and antenna resonances. A 4x1 GZO antenna array was constructed to operate at 5.8 GHz, and the results show approximately 10dBi of lower aperture gain between a copper version of the array and the GZO version of the array. However, the 4x1 GZO array shows an approximate 12dBi increase in gain over a single GZO antenna element. The technology developed in this dissertation has a broader impact other than for smart cities and the upcoming 5G network. Transparent antenna arrays offer sight insensitive military communication systems and eye-worn medical and commercial devices to monitor eye health and other various health signs

Cooperative transport communication in AGV groups using Omni-Curve Parameters

El concepto de los parámetros Omni-Curva se utiliza en el contexto de los robots AGV. Permite que un grupo de vehículos pueda moverse como si fuera uno y, por ejemplo, transportar una carga juntos (transporte cooperativo). Su objetivo es ser universal, es decir, que sirva para cualquier AGV sin importar su configuración de chasis o número de ruedas. Para lograrlo, este concepto calcula la dirección y velocidad de cada rueda conociendo su posición relativa constante dentro del grupo y la trayectoria planeada. Para cada instante en la trayectoria, los parámetros Omni-Curva pueden tomar valores diferentes. Este trabajo se centra en discernir cuál es la mejor forma de asegurar que los AGV poseen los valores actualizados de estos parámetros. Primero se estudian y comparan diferentes tipos de tecnologías de comunicación. Las características más deseadas son robustez y baja latencia. Después, las más interesantes se utilizan para construir un sistema de comunicaciones capaz de enviar y recibir estos parámetros. También se desarrollan métodos para optimizar el flujo de información dentro del grupo de AGV. Finalmente, se comparan y prueban las tecnologías utilizadas y se exponen las conclusiones.The concept of Omni-Curve Parameters (OCPs) is used in the context of Automated Guided Vehicles (AGVs). It allows a group of vehicles to move as if they were one and, for example, carry a load together (cooperative transport). Its aim is to be universal, which means that any vehicle could use it regardless of their chassis configuration or number of wheels. To achieve this, the concept calculates the direction and speed of each wheel knowing their constant relative position in the group and the planned trajectory. For each instant of the trajectory, there can be different values for the OCPs, which are three: floating angle, nominal velocity and nominal curvature. This work focuses on discerning how best to ensure that the AGVs update the values of the OCPs. First, some communication technologies are studied and compared. Robustness and low latency are some of the most desired features. Then, the most appealing ones are used to build a communication system capable of sending and receiving this parameters, as well as some concepts are developed to optimize the information flow of the OCPs through the group. Finally, technologies are compared and tested and conclusions are drawn.Departamento de Ingeniería de Sistemas y AutomáticaMáster en Ingeniería Industria

An optimized planning tool for microwave terrestrial and satellite link design

Today, the internet is fundamental to social inclusion. There are many people that live in remote areas, and the only way to supply internet services is through the use of microwave terrestrial and satellite systems. Thus, it is important to have efficient tools to design and optimize these systems. In this paper, a tool with the objective to shorten the time spent in the design process of microwave terrestrial and satellite point-to-point links is presented. This tool can be applied in academia by engineering students, providing an extended analysis of many sections of a link project design, as well as in professional practice by telecommunication engineering departments, presenting a concise step-by-step interactive design process. This tool uses three-dimensional world visualization, with the Cesium Application Programming Interface (API), to display and analyze site-specific characteristics that can disrupt the link’s quality of service (QoS). Using this visualization, two ray-tracing algorithms were developed to analyze signal diffraction and reflection mainly throughout terrestrial links. Using this new algorithm, an innovative process for signal diffraction and reflection calculations was created. Using updated standards provided by the International Telecommunication Union Radiocommunication Sector (ITU-R), the characteristics of the defined simulated links could be predicted, thus providing the user with the metrics of signal quality and system link budget.info:eu-repo/semantics/publishedVersio

MIMO RADIO-OVER-FIBRE DISTRIBUTED ANTENNA SYSTEM FOR NEXT GENERATION WIRELESS COMMUNICATION

This thesis introduces low-cost implementations for the next generation distributed antenna system (DAS) using analogue radio over fibre. A multiple-input-multiple-output (MIMO) enabled radio over fibre (RoF) system using double sideband (DSB) frequency translation system is proposed. In such a system, the 2x2 MIMO signals can be transmitted to the remote antenna units (RAUs) from the base station via a single optical link. By using the DSB frequency translation, the original single-input-single-output (SISO) DAS can be upgraded into the MIMO DAS without implementing parallel optical links. Experimentally, the DSB frequency translation 2x2 MIMO RoF system transmits 2x2 LTE MIMO signals with 20MHz bandwidth in each channel via a 300m MMF link. The condition number of the system is <10dB within the power equaliser bandwidth which means the MIMO system is well-conditioned and the crosstalk between the channels can be compensated by the MIMO signal processing. To install the DSB frequency translation system in a wideband service-agnostic DAS, the original MIMO signals need to be translated into unoccupied frequency bands over the DAS, which are usually occupied by specific applications that are not to be transmitted over the DAS. The frequency spectrum allocation of the wireless services is analysed showing that by choosing a particular LO frequency (2.2GHz in the UK), in the DSB frequency translation system, the original MIMO signals can always be translated into unoccupied frequency bands so that the same infrastructure can support multiple services. The idea of DSB frequency translation system can not only support MIMO radio over fibre but can also improve the SFDR of a general radio over fibre system. Because when the upper sideband and the lower sideband of the signal after translation are converted back to the original frequency band, the noise adds incoherently but the signals add-up coherently, this gives the system theoretically 2dB 3rd order SFDR improvement. If the idea of the DSB frequency translation is extended into a higher number of sidebands, the system SFDR can be further improved. Experimentally, the system 3rd order SFDR can be improved beyond the intrinsic optical link by 2.7dB by using quadruple sideband (QSB) frequency translation. It means the optical bandwidth in a general RoF system can be traded for the electrical SFDR. By integrating the analogue and the digital RoF systems, a hybrid DAS has been demonstrated, showing that the EVM dynamic range for the 4G LTE service (using digital RoF link) can be improved to be similar to the 3G UMTS service (using analogue RoF link), so that fewer number of RAUs for the LTE services are needed