Polarization and Effects on Hidden Node/Shadowing Margin for TVWS

Dual polarized measurements comparing the received power of a line of sight broadcast signal in the ultra-high frequency band with received power in suburban streets and indoors including high rise buildings are presented in this paper. Both the co-polarized and cross-polarized fades are therefore measured in the different locations. Their purpose is twofold: 1) to identify the importance of using polarization when considering hidden node margins in spectrum sensing of television white spaces and 2) to indicate how polarization can be beneficial in improving the shadowing margin to increase the path loss from the secondary to primary user and thus further protect digital terrestrial television receivers from harmful interference. The impact of polarization in open environments with low clutter or near windows inside high rise buildings is more significant than in densely cluttered spaces experiencing strong multipath

White Space Network Management: Spectrum Quanti cation, Spectrum Allocation and Network Design

Philosophiae Doctor - PhD (Computer Science)The unused spectrum in the television broadcasting frequency bands (so-called TV white spaces) can alleviate the spectrum crunch, and have potential to provide broadband connection to rural areas of countries in the developing world. Current research on TV white spaces focuses on how to detect them accurately, and how they can be shared or allocated to secondary devices. Therefore, the focus of this research is three-fold: to investigate a novel distributed framework, which does not use propagation models in detecting TV white spaces, and suitable for use in countries of the developing world; to investigate a suitable spectrum sharing mechanism for short-time leasing of the TV white spaces to secondary devices; and extend the research to investigate the design of a TV white space-ware network in TV white space frequencies

On the feasibility of the communications in the TVWS spectrum analysis and coexistence issue

In the last decade, the enormous growth in the wireless industry has come from using only a small part of the wireless spectrum, nominally less than 10% under 3 GHz. Nowadays, the vast majority of the available spectral resources have already been licensed. Measurements made by the Federal Communication Commission (FCC) have shown that a great part of the spectrum, although allocated, is virtually unused. For all this reasons, in the last years, several countries have already (USA) or are in the process (EU, China, Japan, South Korea) of switching off analog TV broadcasting in favor of Digital Terrestrial Television (DTT) broadcasting systems and digital switchover plans have driven a thorough review of TV spectrum exploitation. The resulting unused channels within this band are called “TV white spaces” (TVWS). Even after the redistribution of the digital TV channels, the problem of an efficient utilization of the allocated frequencies is still far from being solved. For example, there are still large territorial areas on which, although allocated, the TV channels result unused, due to coverage problems. New spectrum allocation approaches such as the dynamic spectrum access method have been studied. This new concept implies that the radio terminals have the capacity to monitor their own radio environment and consequently adapt to the transmission conditions on whatever frequency band are available (adaptive radio). If this concept is supplemented with the capacity of analyzing the surrounding radio environment in search of white spaces, the term adaptive radio is extended to Cognitive Radio (CR). The spectrum management rule of CR is that all new users for the spectrum are secondary (cognitive) users (SU) and requires that they must detect and avoid the primary (licensed) users (PU) in terms of used frequencies, transmission power and modulation scheme. In the TV bands specifically, the presence of PUs (e.g. TV broadcasters) can be revealed both performing a spectrum sensing operation and considering the information provided by the external databases called “geo-location databases” (GL-DB). The database provides, for a certain location, the list of the free TV channels and the allowable maximum effective isotropic radiated power (EIRP) for transmitting without harmful interference to incumbent users. Decision thresholds are still a critical parameter for protecting services in a scenario where cognitive devices would be operating. There are cases where the approach based on GL Spectrum Occupancy DB might not be available, either because the database does not exist for that area (for example in non densely populated areas) or in the case that access to the database is not possible (deep indoor operation, low populated areas etc.). Several studies have suggested that radio noise has increased significantly over the last decades and consequently the assumptions about decision thresholds and interference protection ratios might be outdated. The Hidden Node Margin (HNM) is a parameter that quantifies the difference between the potential interfered signal values at the location where it is measured or estimated by the cognitive device, and the actual value at the location where the receiving antenna for this signal is located. HNM is a key parameter to define the protection requirements that cognitive devices must comply in order not to create any harmful interference to broadcast receiving systems. In this context, this thesis goes in a precise direction, with four main topics related to the feasibility of communication cognitive systems operating in the TVWS, considering coexistence as the main operational issue. The first topic studies new spectrum sensing approaches in order to improve the more critical functionality of CRs. In the second topic an unlicensed indoor short-range distribution system for the wireless retransmission in the DTT band of High definition TV (HDTV) contents with immediate implementations as home entertainment systems has been carried out. The third topic of this thesis is about a particular database developed in order to provide information to easily calculate HNM values and associated statistics, TV Channel Occupancy and Man Made Noise Upper Limits. The empirical data for this work has been recorded in different locations of Spain and Italy during 2011 and 2012 thanks to the partnership between the Department of Electrical and Electronic Engineering (D.I.E.E.) of the University of Cagliari and the Department of Electronics and Telecommunications of the University of Bilbao (UPV/EHU). Finally in the last topic we focus on the IEEE 802.22 WRAN standard evaluating, thanks to extended measurements, the performance of an 802.22 system operating into the same coverage range of a DTT receiver

An Assessment of Path Loss Tools and Practical Testing of Television White Space Frequencies for Rural Broadband Deployments

Broadband internet has grown to become a major part of our daily routines. With this growth increase, those without direct access will not be afforded the same opportunities that come with it. The need for ubiquitous coverage of broadband Internet is clear to provide everyone these opportunities. Rural environments are an area of concern of falling behind the growth as the low population densities make wired broadband solutions cost prohibitive. Wireless options are often the only option for many of these areas; WiFi, cellular, and WiMAX networks are currently used around the world, but with the opening of the unused broadcast television frequencies, deemed TV White Space (TVWS), a new option is hitting the market. This new technology needs to be assessed before it can be seen as a viable solution. The contribution of this work is two-fold. First, findings from a real, ongoing trial of commercially available TVWS radios in the area surrounding the University of New Hampshire campus are presented. The trial shows that though the radios can provide Internet access to a distance of at least 12.5 km, certain terrain and foliage characteristics of the path can form coverage holes in that region. The second contribution explores the use of empirical path loss models to predict the path loss, and compares the predictions to actual path loss measurements from the TVWS network setup. The Stanford University Interim (SUI) model and a modified version of the Okumura-Hata model provide the lowest root mean squared error (RMSE) for the setup. Additionally, the deterministic Longley-Rice model was explored with the Radio Mobile prediction software. It was determined that without extensively tuning the foliage component of the algorithm, the model could produce significant prediction errors, resulting in a trade-off between low cost, un-tuned predictions, and prediction accuracy

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

Next-Generation Public Safety Systems Based on Autonomous Vehicles and Opportunistic Communications

An emergency scenario is characterized by the unpredictability of the environment conditions and by the scarcity of the available communication infrastructures. After a natural or human disaster, the main public and private infrastructures are partially damaged or totally destroyed. These infrastructures include roads, bridges, water supplies, electrical grids, telecommunications and so on. In these conditions, the first rescue operations executed by the public safety organizations can be very difficult, due to the unpredictability of the disaster area environment and the lack in the communications systems. The aim of this work is to introduce next-generation public safety systems where the main focus is the use of unmanned vehicles that are able to exploit the self-organizing characteristics of such autonomous systems. With the proposed public safety systems, a team of autonomous vehicles will be able to overcome the hazardous environments of a post disaster scenario by introducing a temporary dynamic network infrastructure which enables the first responders to cooperate and to communicate with the victims involved. Furthermore, given the pervasive penetration of smart end-user devices, the emergence of spontaneous networks could constitute promising solutions to implement emergency communication systems. With these systems the survivors will be able to self-organize in a communication network that allows them to send alerts and information messages towards the rescue teams, even in absence of communication infrastructures

Cooperative Radio Communications for Green Smart Environments

The demand for mobile connectivity is continuously increasing, and by 2020 Mobile and Wireless Communications will serve not only very dense populations of mobile phones and nomadic computers, but also the expected multiplicity of devices and sensors located in machines, vehicles, health systems and city infrastructures. Future Mobile Networks are then faced with many new scenarios and use cases, which will load the networks with different data traffic patterns, in new or shared spectrum bands, creating new specific requirements. This book addresses both the techniques to model, analyse and optimise the radio links and transmission systems in such scenarios, together with the most advanced radio access, resource management and mobile networking technologies. This text summarises the work performed by more than 500 researchers from more than 120 institutions in Europe, America and Asia, from both academia and industries, within the framework of the COST IC1004 Action on "Cooperative Radio Communications for Green and Smart Environments". The book will have appeal to graduates and researchers in the Radio Communications area, and also to engineers working in the Wireless industry. Topics discussed in this book include: • Radio waves propagation phenomena in diverse urban, indoor, vehicular and body environments• Measurements, characterization, and modelling of radio channels beyond 4G networks• Key issues in Vehicle (V2X) communication• Wireless Body Area Networks, including specific Radio Channel Models for WBANs• Energy efficiency and resource management enhancements in Radio Access Networks• Definitions and models for the virtualised and cloud RAN architectures• Advances on feasible indoor localization and tracking techniques• Recent findings and innovations in antenna systems for communications• Physical Layer Network Coding for next generation wireless systems• Methods and techniques for MIMO Over the Air (OTA) testin

Cooperative Radio Communications for Green Smart Environments

The demand for mobile connectivity is continuously increasing, and by 2020 Mobile and Wireless Communications will serve not only very dense populations of mobile phones and nomadic computers, but also the expected multiplicity of devices and sensors located in machines, vehicles, health systems and city infrastructures. Future Mobile Networks are then faced with many new scenarios and use cases, which will load the networks with different data traffic patterns, in new or shared spectrum bands, creating new specific requirements. This book addresses both the techniques to model, analyse and optimise the radio links and transmission systems in such scenarios, together with the most advanced radio access, resource management and mobile networking technologies. This text summarises the work performed by more than 500 researchers from more than 120 institutions in Europe, America and Asia, from both academia and industries, within the framework of the COST IC1004 Action on "Cooperative Radio Communications for Green and Smart Environments". The book will have appeal to graduates and researchers in the Radio Communications area, and also to engineers working in the Wireless industry. Topics discussed in this book include: • Radio waves propagation phenomena in diverse urban, indoor, vehicular and body environments• Measurements, characterization, and modelling of radio channels beyond 4G networks• Key issues in Vehicle (V2X) communication• Wireless Body Area Networks, including specific Radio Channel Models for WBANs• Energy efficiency and resource management enhancements in Radio Access Networks• Definitions and models for the virtualised and cloud RAN architectures• Advances on feasible indoor localization and tracking techniques• Recent findings and innovations in antenna systems for communications• Physical Layer Network Coding for next generation wireless systems• Methods and techniques for MIMO Over the Air (OTA) testin