Analyzing Options for Airborne Emergency Wireless Communications

In the event of large-scale natural or manmade catastrophic events, access to reliable and enduring commercial communication systems is critical. Hurricane Katrina provided a recent example of the need to ensure communications during a national emergency. To ensure that communication demands are met during these critical times, Idaho National Laboratory (INL) under the guidance of United States Strategic Command has studied infrastructure issues, concerns, and vulnerabilities associated with an airborne wireless communications capability. Such a capability could provide emergency wireless communications until public/commercial nodes can be systematically restored. This report focuses on the airborne cellular restoration concept; analyzing basic infrastructure requirements; identifying related infrastructure issues, concerns, and vulnerabilities and offers recommended solutions

The evolving nature of competition in the wireless ecosystem : emergent opportunities and threats

Thesis (S.M.)--Massachusetts Institute of Technology, System Design and Management Program, 2009.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.Cataloged from student submitted PDF version of thesis.Includes bibliographical references.By the end of 2008, there are over 4 billion mobile cellular subscriptions worldwide, translating into a penetration rate of 61%. In developed economies like the United States, the penetration rate has reached over 85%. Even though the subscriber numbers are reaching saturation levels, the revenues of mobile operators continue to grow at a double-digit rate. This is primarily because of an increase in data usage over cellular networks. Mobile handsets have become increasingly powerful and rival the capabilities of personal computers from just a few years ago. These devices can be used to run a variety of applications and are fast becoming the medium of choice for accessing the Internet. Cellular networks are also becoming increasingly powerful in their ability to carry large amounts of data. This evolution in capabilities has attracted a variety of new players to the wireless ecosystem changing the nature of interaction within the ecosystem. The central role played by the wireless operators is increasingly challenged by these new entrants creating both new opportunities and new threats for all the participants in the ecosystem. This thesis will explore the structure of the wireless ecosystem as it exists today and analyze how competition between various layers and within each layer has played out. Further, it will look at the new ways in which the participants are competing with each other and how this results in emergent opportunities and threats. Finally, the thesis will draw lessons from the Internet revolution and the personal computing ecosystem to predict how the platform wars are likely to play out and who has the opportunity to become the dominant player in the new ecosystem.by Nagarjuna Venna.S.M

Implementation Aspects of UMTS 900 MHz/2100 MHz for High Altitude Platforms

Projecte realitzat en col.laboració amb el centre Tampere University of TechnologyHigh Altitude Platforms (HAPs) represent an alternative to terrestrial mobile telecommunications. The aim of HAPs is to offer a feasible solution for the radio access layer of this kind of networks. The strong point of HAPs resides in the fact that they bring together the best features of terrestrial and satellite systems. HAPs have been widely proposed for deploying telecommunication services such as third generation mobile networks. In Europe, third generation of mobile communications system is using UMTS. It has being widely deployed in the last years but still there are certain areas where 3G coverage is not available. Especially in rural areas with low population density, where the operators did not find a cost efficient way to deploy UMTS services. As a result, UMTS in 900 MHz band emerges as a possible way to improve UMTS coverage for these areas, and combining with a HAP-based deployment, a cost efficient way for a widely deployment in sparsely populated and remote areas for 3G services. The work shown in this thesis is a comparison of network simulations obtained from the use of HAPs in the radio access network of UMTS using 900 MHz band and 2100 MHz band. The study was aimed to find the impact of carrier frequency on coverage for a single HAP scenario using different deployment strategies. An antenna study has also been done in order to see the impact of antenna beamwidth on UMTS system. The results obtained reveal that the decrease in the carrier frequency caused a clear increase in the coverage, when correct distance between cells was selected. Consequently the results obtained show the variation of the network performance with the separation between cells using both carrier frequencies, 2100 MHz and 900 MHz

Jammers for mobile cellular systems applied to unauthorized UAVs

This research aims to explore jamming on digital mobile systems, with an initial focus towards the 2G and Global System of Mobile Communications (GSM) technologies. The main goal is to develop a jammer with an efficiency and complexity greater than the existent ones, capable to better disrupt digital mobile systems. The study consists of an analysis of the different techniques of jamming, that can disrupt the mobile cellular system’s communication, through a series of simulations using the Software Defined Radio (SDR) and the GNU Radio ecosystem. The same techniques will then be studied and evaluated in real life scenarios in order to select which one is the best regarding spectral efficiency, energy and complexity. Finally, the jammer returning the best results will be the one chosen to contribute sustainably for the issue with flying drones on restrict areas, such as airports and residential zones, and thus, decrease the number of accidents which nowadays happen usually with this kind of aircrafts.Neste estudo será feita uma abordagem ao jamming em sistemas móveis digitais, dando um maior foco inicial à tecnologia 2G, Sistema Global para Comunicações Móveis (GSM). O objetivo principal será o desenvolvimento de um sinal jammer, diferente dos já existentes em termos de eficiência e complexidade, capaz de causar interferência em sistemas móveis celulares. Será feito então uma análise às diferentes técnicas de interferência de sinal, capazes de perturbar a comunicação em sistemas móveis celulares, através da realização de simulações a partir da tecnologia Software Defined Radio (SDR) nomeadamente, a plataforma GNU Radio. As mesmas técnicas também serão estudadas e avaliadas num cenário real, de forma a fazer-se a seleção da melhor em termos de eficiência espectral, energia e complexidade. Finalmente, a técnica de jamming que demonstrar melhores resultados, irá representar o jammer que poderá contribuir de forma sustentável para a problemática da circulação de drones em zonas restritas, como aeroportos e zonas residenciais, para a diminuição dos acidentes, atualmente registados, com este tipo de aeronaves

Contextproxy : a location-aware HTTP proxy server to support web based context-aware services and applications

Cataloged from PDF version of article.The pervasion of computing in our physical world promises more than the ubiquitous availability of computing resources; totally new and exciting interaction schemes are to be explored. Context-awareness, one of the most important aspects of ubiquitous computing, enables applications that make use of their users’ context to provide dynamically adapting information and services to their users or to other applications. Although the technological infrastructure to support ubiquitous and context-aware applications is being deployed rapidly, the standards and the best practices for the interactions of various components in a context-aware application are still missing. In our work we have developed a location-aware HTTP proxy server, called ContextProxy that runs on the popular Symbian platform. ContextProxy acts as a standard HTTP proxy server from the client application’s perspective but it augments the service request of the client with the available location information while submitting the request to the service provider. This allows the existing nomadic applications to immediately become locationaware if they can be configured to make use of a standard HTTP proxy which is a common scheme for web based applications. And also it is possible to write new nomadic applications without considering the context-awareness aspect at the service requestor level. The contextual information added by ContextProxy can then be utilized by the service provider to dynamically adapt its services according to the service requestor’s context.Uluçınar, Alper RifatM.S

Energy-Optimal Path Planning for Solar-Powered Aircraft in Level Flight

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/76295/1/AIAA-2007-6655-400.pd

Infrastructure Design, Signalling and Security in Railway

Railway transportation has become one of the main technological advances of our society. Since the first railway used to carry coal from a mine in Shropshire (England, 1600), a lot of efforts have been made to improve this transportation concept. One of its milestones was the invention and development of the steam locomotive, but commercial rail travels became practical two hundred years later. From these first attempts, railway infrastructures, signalling and security have evolved and become more complex than those performed in its earlier stages. This book will provide readers a comprehensive technical guide, covering these topics and presenting a brief overview of selected railway systems in the world. The objective of the book is to serve as a valuable reference for students, educators, scientists, faculty members, researchers, and engineers

WiMAX HAPS-based downlink performance employing geometrical and statistical propagation channel characteristics

The evolution to a well-expected technology in wireless-communications maturity is in progress. Complementary applications are being suggested for such purposes, which might be possibly effective from the already ongoing research on high-altitude-platform systems. Herein, we introduce a HAPS-based system for delivering broadband communications intended to be operational at L band. A physical-statistical channel model for the HAPSto-fixed-terrestrial terminal provision is derived from urban geometrical radio-coverage considerations with a simple diffraction theory. The stratospheric broadband channel model is fulfi lled with the two channel-state situations related to the direct and specular rays, plus multipath. The fi rst state consists of predicting the performance for which the line-of-sight path can exist between HAPS and the still terminal at street level. The second channel state refers to modeling the statistical fading characteristics for the shadowing condition. The system implementation is approximated and analyzed by performing intensive simulation-aided modeling. The proposed hypotheses use empirical data derived from land-mobile-satellite communication-system records. Because the systems require robust, reliable, and future standardization results, IEEE 802.16™-2004 PHYlayer technical specifi cations are used to accomplish the WiMAX HAPS-based downlink performance evaluation.Peer ReviewedPostprint (published version

Internationalisation of Innovation: Why Chip Design Moving to Asia

This paper will appear in International Journal of Innovation Management, special issue in honor of Keith Pavitt, (Peter Augsdoerfer, Jonathan Sapsed, and James Utterback, guest editors), forthcoming. Among Keith Pavitt's many contributions to the study of innovation is the proposition that physical proximity is advantageous for innovative activities that involve highly complex technological knowledge But chip design, a process that creates the greatest value in the electronics industry and that requires highly complex knowledge, is experiencing a massive dispersion to leading Asian electronics exporting countries. To explain why chip design is moving to Asia, the paper draws on interviews with 60 companies and 15 research institutions that are doing leading-edge chip design in Asia. I demonstrate that "pull" and "policy" factors explain what attracts design to particular locations. But to get to the root causes that shift the balance in favor of geographical decentralization, I examine "push" factors, i.e. changes in design methodology ("system-on-chip design") and organization ("vertical specialization" within global design networks). The resultant increase in knowledge mobility explains why chip design - that, in Pavitt's framework is not supposed to move - is moving from the traditional centers to a few new specialized design clusters in Asia. A completely revised and updated version has been published as: " Complexity and Internationalisation of Innovation: Why is Chip Design Moving to Asia?," in International Journal of Innovation Management, special issue in honour of Keith Pavitt, Vol. 9,1: 47-73.