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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

PCM Telemetry Downlink for IRIG 106 Chapter 10 Data

Pappas, Johnny, Bagó, Balázs, Cranley, Nikki, Poisson, Gabriel 10 1900 (has links)
ITC/USA 2013 Conference Proceedings / The Forty-Ninth Annual International Telemetering Conference and Technical Exhibition / October 21-24, 2013 / Bally's Hotel & Convention Center, Las Vegas, NV / Since both airborne and ground applications are able to handle and process IRIG 106, Chapter 10 standard data (further referred to as C10) from files or from live streaming UDP network data, it is a logical extension of the standard to telemeter network data from the air to the ground support systems with little or no modification. This paper describes a method to transport C10 compliant packets over a Class II, telemetry stream (C10 TMDL) which is fully compatible with existing encryptors, transmitters, receivers, and decryptors.
12

Small Satellite Applications of Commercial off the Shelf Radio Frequency Integrated Circuits

Graves, John 2011 December 1900 (has links)
Within the first decade of the 21st century, the aerospace community has seen many more opportunities to launch small spacecraft in the 10 to 100 kg mass class. Coupled with this has been consistent interest from the government in developing small-spacecraft platforms to expand civil and military mission possibilities. Small spacecraft have also given small organizations such as universities an increased access to space. Because small satellites are limited in size, power, and mass, new and often nontraditional capabilities must be explored and developed to make them viable and attractive when compared with larger and more proven spacecraft. Moreover, small organizations that wish to contribute technically are often limited by the small size of their teams and available resources, and need creative solutions for meeting mission requirements. A key need is in space-to-ground communications. Complex missions typically require large amounts of data transfer to the ground and in a timely fashion. Available options trade hardware cost, available ground stations or networks, available operating-frequency range, data-rate performance, and ease of use. A system for small spacecraft will be presented based upon Radio Frequency Integrated Circuits (RFIC) that minimizes development effort and maximizes interface control to meet typical small-spacecraft communications requirements. RFICs are low-cost components that feature pre-built radio hardware on a chip that can be expanded easily by developers with little or no radio experience. These devices are widespread in domestic applications for short-range connectivity. A preliminary design and prototype is presented that meets basic spaceflight requirements, offers data rates in the 55 to 85 kbps range, and has completed basic proof-of-concept testing. While there are higher-data-rate alternatives in existence, the solution presented here strikes a useful balance among data rate, parts cost, and ease of use for non experts, and gives the user operational control necessary to make air-to-ground communications time effective.
13

Blind signature waveform estimation and linear multiuser detection in direct sequence code division multiple access systems

Zarifi, Keyvan. Unknown Date (has links)
Techn. University, Diss., 2007--Darmstadt.
14

Vorentzerrung für die räumlich überlagerte Kommunikation mit verteilten Empfängern /

Habendorf, René January 2008 (has links)
Zugl.: Dresden, Techn. Universiẗat, Diss., 2008.
15

Empfänger-Strukturen für die UMTS-Abwärtsstrecke

Knoche, Klaus January 2009 (has links)
Zugl.: Bremen, Univ., Diss., 2009
16

Robust Power Loading for the TDD MISO Downlink with Outage Constraints

Sohrabi, Foad 10 1900 (has links)
<p>We consider the problem of power allocation for the single-cell multiple-input single- output (MISO) downlink in a time division duplex (TDD) system. In such systems, the base station (BS) acquires information about the channel state during the training component of the uplink phase. The resulting estimation errors are modeled prob- abilistically, and the receivers specify quality-of-service (QoS) constraints in terms of a target signal-to-interference-and-noise ratio that is to be achieved with a given outage probability. For a fixed beamforming structure, we seek a power allocation that minimizes the transmission power required to satisfy the users’ QoS requests.</p> <p>The proposed approach to that problem begins with the observation that for TDD systems the channel estimation error at the base station can be modeled as being additive and Gaussian. Under that model, we obtain a precise deterministic characterization of the outage probability, and mildly conservative approximations thereof. Although the resulting deterministic optimization problems are not convex, we have been able to obtain good solutions using straightforward coordinate update algorithms. In fact, these solutions provide significantly better performance than the existing approaches, which are based on convex restrictions, because the proposed approximations are less conservative. By developing some approximations of the precise deterministic characterization of the outage probability, we develop algorithms that have good performance and much lower computational cost.</p> / Master of Applied Science (MASc)
17

An Advanced Commanding and Telemetry System

Hill, Maxwell G. G. 11 1900 (has links)
International Telemetering Conference Proceedings / October 29-November 02, 1990 / Riviera Hotel and Convention Center, Las Vegas, Nevada / The Loral Instrumentation System 500 configured as an Advanced Commanding and Telemetry System (ACTS) supports the acquisition of multiple telemetry downlink streams, and simultaneously supports multiple uplink command streams for today’s satellite vehicles. By using industry and federal standards, the system is able to support, without relying on a host computer, a true distributed dataflow architecture that is complemented by state-of-the-art RISC-based workstations and file servers.
18

QoS_of_VoIP_in_Wireless_Networks / QoS_för_VoIP_i_trådlösa_nätverk

Iqbal, Naveed, Cheema, Fahad-Mumtaz January 2009 (has links)
In this thesis we have focused in the wireless environment and how to run voice application over it. Conducive environment that makes it possible for the voice services to run in wireless is necessary. As we know this well that wireless is a contemporary technology due to it low cost and its effectiveness, and one major advantage of it is the mobility that is one fell free to move anywhere but have the access to the resource. So this makes wireless networks of great value, we in this thesis have focused on wireless LAN’s. In second part of the thesis we have shed some light on the VoIP showing how it works in the wireless environment. Analysis phase is relatively more important phase then the previous section which shows issues or hindrances in carrying voice over wireless environment. This analysis shows that these issues still prevails and should be addresses and the corresponding results are also discussed and by looking at those results we have derived a summery out of it. Next chapter we firstly tried to explain why we have chosen specific protocols and then showing some graphical representation measurements that are to address the problem based on the work done. We tried to evaluate EDCF and DCF as these play important role in handling real time applications like voice. After that we proposed a scheme through which these effects can be minimized and to enhance the method is necessary to avoid the issues still in effect. / Thesis is Part for Master program in Electrical Engineering with Emphasis on Telecommunication(2007-2009).We have had a very nice time doing this thesis as there was alot of learning. Our examinator was allways there to help us, we are thankfull to Richard for his endless support.
19

Models and optimisation methods for interference coordination in self-organising cellular networks

Lopez-Perez, David January 2011 (has links)
We are at that moment of network evolution when we have realised that our telecommunication systems should mimic features of human kind, e.g., the ability to understand the medium and take advantage of its changes. Looking towards the future, the mobile industry envisions the use of fully automatised cells able to self-organise all their parameters and procedures. A fully self-organised network is the one that is able to avoid human involvement and react to the fluctuations of network, traffic and channel through the automatic/autonomous nature of its functioning. Nowadays, the mobile community is far from this fully self-organised kind of network, but they are taken the first steps to achieve this target in the near future. This thesis hopes to contribute to the automatisation of cellular networks, providing models and tools to understand the behaviour of these networks, and algorithms and optimisation approaches to enhance their performance. This work focuses on the next generation of cellular networks, in more detail, in the DownLink (DL) of Orthogonal Frequency Division Multiple Access (OFDMA) based networks. Within this type of cellular system, attention is paid to interference mitigation in self-organising macrocell scenarios and femtocell deployments. Moreover, this thesis investigates the interference issues that arise when these two cell types are jointly deployed, complementing each other in what is currently known as a two-tier network. This thesis also provides new practical approaches to the inter-cell interference problem in both macro cell and femtocell OFDMA systems as well as in two-tier networks by means of the design of a novel framework and the use of mathematical optimisation. Special attention is paid to the formulation of optimisation problems and the development of well-performing solving methods (accurate and fast).
20

Adaptive harvest-then-transmit for a two-tier heterogeneous wireless network

Ogundipe, Adedayo 12 August 2016 (has links)
Different techniques are being implemented in modern communication networks to ensure that their coverage, capacity, and other user-experience requirements are always met. In this thesis, I consider multi-antenna techniques, energy harvesting, and the dense deployment of small cell base stations in a two-tiered wireless powered communication network (WPCN) where multi-antenna transmitters utilize a Harvest Then Transmit (HTT) protocol to coordinate wireless energy harvesting and information transmission with their associated users. To satisfy network throughput requirements at all user positions, I formulate multi-constraint optimization problems to maximize the minimum data rate at both tier and network levels, solving the resulting non-convex expressions with an algorithm which incorporates the Perron-Frobenius non-negative matrix theory for alternate parameter optimization. I also present a less complex solution methodology, compared the performance of both and provided interesting insights on my findings. / October 2016

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