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Dissertations / Theses on the topic 'Electrical Communication Engineering'
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Chen, Fangzhou. "WIRELESS COMMUNICATION UNDER IMPERFECT SOURCE/CHANNEL INFORMATION." The Ohio State University, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=osu1503062069085737.
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Wan, Jun S. M. Massachusetts Institute of Technology. "All-to-all communication with low communication cost." Thesis, Massachusetts Institute of Technology, 2018. http://hdl.handle.net/1721.1/120398.
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Thesis: S.M., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 2018.<br>Cataloged from PDF version of thesis.<br>Includes bibliographical references (pages 61-64).<br>In an all-to-all broadcast, every user wishes to broadcast its message to all the other users. This is a process that frequently appears in large-scale distributed systems such as voting and consensus protocols. In the classic solution, a user needs to receive n messages and n signatures where n is the number of users in the network. This is undesirable for large-scale distributed systems that contain millions or billions of users and can be the throughput bottleneck for some existing systems. In this thesis, we propose two protocols for the all-to-all broadcast problem. Our protocols upper bound the number of bits each user receives by [Theta](n log log2 n), which is a huge improvement from the conventional n times the signature size. Besides the all-to-all protocol, we also provide new results regarding random graphs and regular graphs. These results are used in our protocol to prove its efficiency. But they are interesting by themselves and have independent theoretic value.<br>by Jun Wan.<br>S.M.
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Ncube, Ariage T. "Performance evaluation of a communication network." Master's thesis, University of Cape Town, 1995. http://hdl.handle.net/11427/21963.
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This work uses a simulation package to analyze the performance of a specific X.25 Value Added Communication Network (VAN), comprising a Network Administrator and a cluster of Network Concentrators (NCs). Detailed models of the network elements are developed, and system performance is analyzed in terms of network response time for the terminal users communicating across the network, identification of areas of bottlenecks in the NC system, and NC system throughput. The througput parameter is represented by the percentage of the output traffic to the load offered from the network of terminals. The performance of the Network Administrator system is also modeled, focusing particularly on the automatic restoration of service to failed NCs through downloading of operating software sets over the X.25 network. The final part consists of a model of a modification of the network manager components of the network as proposed in the DM upgrade project. In this section, NC loading time is again the desired performance indicator. It is shown that there is no noticeable improvement in this parameter between the original system and the proposed upgrade, both systems having a minimum loading time of about 3.5 to 6 minutes for a small network.
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Sanderson, Josh. "Hierarchical Modulation Detection of Underwater Acoustic Communication Signals Through Maximum Likelihood Combining." Wright State University / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=wright1410872323.
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Garg, Kamal. "Ultra Wideband Antennas for Personal Communication Devices." FIU Digital Commons, 2001. https://digitalcommons.fiu.edu/etd/3842.
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The objective of this thesis is to determine and analyze the characteristics of ultra wideband antennas for personal communication systems. For this purpose a diamond dipole antenna, an ultra wideband antenna designed by Time Domain Corp, is studied and various parameters, like Sil and the VSWR of the antenna are calculated. These parameters are determined by simulating the antenna using the XFDTD software and the MultiStrip program. The results thus obtained are validated by measurements on the network analyzer using the antenna model. A bowtie antenna with the same dimensions as the diamond dipole antenna is suggested and performance of these two antennas is compared. Subsequently a new geometry of bowtie antenna is suggested and the effect of varying the cone half angle on the VSWR and Sil parameters of the antenna is investigated. Further, a comparison is made between the new model of the bowtie antenna and the diamond dipole antenna. Towards the end, a new ultra wideband antenna using a bowtie is suggested.
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Mazzaro, Gregory James. "Time-Frequency Effects in Wireless Communication Systems." NCSU, 2009. http://www.lib.ncsu.edu/theses/available/etd-09292009-115014/.
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Time-frequency effects in wireless communication systems caused by narrowband resonances and coupled with device nonlinearities are revealed as new sources of co-site interference, exploited for the metrology of bandpass circuits, and employed to linearize amplitude-modulated transmissions. The transient properties of bandpass filters are found to last much longer than traditional time/bandwidth rules-of-thumb. The cause of this long-tail behavior is attributed to the coupled-resonator structure of the filter circuit. A solution method which uses lowpass prototyping is developed to reduce, by a factor of two, the complexity of the differential equation set describing a narrowband filter's transient response. Pulse overlap caused by the frequency dependence of long tails produced by filters is shown to cause intersymbol interference and intermodulation distortion in RF front-ends during frequency-hopped communications. The same properties which cause the ISI and IMD are used to develop three new transient methods for measuring resonant circuit parameters and a one-port method for extracting the operating band of a filter. A new signal-processing technique which combines time- and frequency-selectivity, Linear Amplification by Time-Multiplexed Spectrum, is developed to reduce IMD associated with amplitude modulation. Distortion reduction is demonstrated experimentally for multisines up to 20 tones.
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Shoemaker, David R. (David Robert). "An optimized hardware architecture and communication protocol for scheduled communication." Thesis, Massachusetts Institute of Technology, 1997. http://hdl.handle.net/1721.1/42660.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1997.<br>Includes bibliographical references (p. 173-177).<br>by David Shoemaker.<br>Ph.D.
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Juba, Brendan (Brendan Andrew). "Universal semantic communication." Thesis, Massachusetts Institute of Technology, 2010. http://hdl.handle.net/1721.1/62423.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2010.<br>Cataloged from PDF version of thesis.<br>Includes bibliographical references (p. 325-334).<br>Is meaningful communication possible between two intelligent parties who share no common language or background? We propose that this problem can be rigorously addressed by explicitly focusing on the goals of the communication. We propose a theoretical framework in which we can address when and to what extent such semantic communication is possible. Our starting point is a mathematical definition of a generic goal for communication, that is pursued by agents of bounded computational complexity. We then model a "lack of common language or background" by considering a class of potential partners for communication; in general, this formalism is rich enough to handle varying degrees of common language and backgrounds, but the complete lack of knowledge is modeled by simply considering the class of all partners with which some agent of similar power could achieve our goal. In this formalism, we will find that for many goals (but not all), communication without any common language or background is possible. We call the strategies for achieving goals without relying on such background universal protocols. The main intermediate notions introduced by our theory are formal notions of feedback that we call sensing. We show that sensing captures the essence of whether or not reliable universal protocols can be constructed in many natural settings of interest: we find that across settings, sensing is almost always sufficient, usually necessary, and generally a useful design principle for the construction of universal protocols. We support this last point by developing a number of examples of protocols for specific goals. Notably, we show that universal delegation of computation from a space-efficient client to a general-purpose server is possible, and we show how a variant of TCP can allow end-users on a packet network to automatically adapt to small changes in the packet format (e.g., changes in IP). The latter example above alludes to our main motivation for considering such problems, which is to develop techniques for modeling and constructing computer systems that do not require that their components strictly adhere to protocols: said differently, we hope to be able to design components that function properly with a sufficiently wide range of other components to permit a rich space of "backwards-compatible" designs for those components. We expect that in the long run, this paradigm will lead to simpler systems because "backwards compatibility" is no longer such a severe constraint, and we expect it to lead to more robust systems, partially because the components should be simpler, and partially because such components are inherently robust to deviations from any fixed protocol. Unfortunately, we find that the techniques for communication under the complete absence of any common background suffer from overhead that is too severe for such practical purposes, so we consider two natural approaches for introducing some assumed common background between components while retaining some nontrivial amount of flexibility. The first approach supposes that the designer of a component has some "belief" about what protocols would be "natural" to use to interact with other components; we show that, given sensing and some sufficient "agreement" between the beliefs of the designers of two components, the components can be made universal with some relatively modest overhead. The second approach supposes that the protocols are taken from some restricted class of functions, and we will see that for certain classes of functions and simple goals, efficient universal protocols can again be constructed from sensing. Actually, we show more: the special case of our model described in the second approach above corresponds precisely to the well-known model of mistake-bounded on-line learning first studied by Barzdirs and Frievalds, and later considered in more depth by Littlestone. This connection provides a reasonably complete picture of the conditions under which we can apply the second approach. Furthermore, it also seems that the first approach is closely related to the problem of designing good user interfaces in Human-Computer Interaction. We conclude by briefly sketching the connection, and suggest that further development of this connection may be a potentially fruitful direction for future work.<br>by Brendan Juba.<br>Ph.D.
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Du, Hao. "Optical wireless MIMO communication." Thesis, University of Warwick, 2015. http://wrap.warwick.ac.uk/70945/.
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This thesis provides an in-depth investigation and evaluation of infrared optical wireless MIMO communication systems to be applied in both indoor and outdoor environment. The principle objective of the research is to demonstrate both the advantages and disadvantages of the optical wireless MIMO systems using different modulation types. The first part provided analyses of important OW configurations using APD receivers using WMC model and SISO, MISO, SIMO and MIMO configuration. Thus, an analytical expression for 2-1 MISO, 1-2 SIMO and MIMO was successfully developed. This part also illustrates the coding gains possible using diversity schemes for APD OW systems. In the presence of strong fading, the SISO approach is rendered virtually useless, whereas diversity offers acceptable BER values. The results underpin the approach of this thesis, where indoor PIN diode based experimental measurements confirm the gains offered by diversity. In the second part of the work, several optical wireless MIMO systems applicable for the indoor environment are developed for three different modulation types, OOK modulation, PPM modulation and SIR-RZI modulation. These modulations are used in optical MIMO systems are studied for which, mathematical models that evaluate the BER performance of the MIMO system for different axis displacement and for different distances between transmitters and receivers. Based on the results, the PPM system has been shown to present the best BER performance, including high interference-resistance capability. A group of new mathematical models have been evaluated, which demonstrates a high level of correlation with the results derived from empirical models at 93%. Thus, the mathematical models developed and used for the specified evaluation appear to correspond reasonably well, and can be applied in future research on these aspects.
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Wang, Hao Chen Biao. "Transceiver design issues for wireless multicarrier communication systems." Related electronic resource: Current Research at SU : database of SU dissertations, recent titles available full text, 2004. http://wwwlib.umi.com/cr/syr/main.
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Lupupa, Mzabalazo. "Transmit antenna selection in fading wireless communication systems." Master's thesis, University of Cape Town, 2009. http://hdl.handle.net/11427/12110.
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Includes abstract.<br>Includes bibliographical references (leaves 79-83).<br>To address the drawbacks associated with multiple-input multiple-output (MIMO) systems, we propose the use of the transmit antenna selection technique. In transmit antenna selection, the best performing antenna(s) is selected from all the available transmit antennas for transmission. Transmit antenna selection reduces the number of radio frequency chains, and the system complexity while still achieving the goals of multiple antenna systems. In this thesis the performance of a MIMO system employing transmit antenna selection and maximal-ratiocombining is studied.
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Graflund, Marcus. "COMMUNICATION USING ANUNDERWATER SONAR." Thesis, Mälardalens högskola, Akademin för innovation, design och teknik, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:mdh:diva-36722.
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Cryan, R. A. "Communication systems." Thesis, University of Huddersfield, 1999. http://eprints.hud.ac.uk/id/eprint/7477/.
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Pakravan, Mohammad Reza. "Indoor infrared wireless communication channels." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape4/PQDD_0016/NQ57061.pdf.
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Tatikonda, Sekhar Chandra. "Control under communication constraints." Thesis, Massachusetts Institute of Technology, 2000. http://hdl.handle.net/1721.1/16755.
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Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2000.<br>Includes bibliographical references (p. 224-228).<br>This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.<br>by Sekhar Chandra Tatikonda.<br>Ph.D.
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Brööks, Andrëw G. (Brööks Zoz). "Coördinating human-robot communication." Thesis, Massachusetts Institute of Technology, 2007. http://hdl.handle.net/1721.1/38888.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2007.<br>This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.<br>Includes bibliographical references (p. 188-210).<br>As robots begin to emerge from the cloisters of industrial and military applications and enter the realms of coöperative partners for people, one of the most important facets of human-robot interaction (HRI) will be communication. This can not merely be summarized in terms of the ongoing development into unimodal communication mechanisms such as speech interfaces, which can apply to any technology. Robots will be able to communicate in physically copresent, "faceto-face" interactions across more concurrent modalities than any previous technology. Like many other technologies, these robots will change the way people work and live, yet we must strive to adapt robots to humans, rather than the reverse. This thesis therefore contributes mechanisms for facilitating and influencing human-robot communication, with an explicit focus on the most salient aspect that differentiates robots from other technologies: their bodies. In order to communicate effectively with humans, robots require supportive infrastructure beyond the communications capabilities themselves, much as do the humans themselves. They need to be able to achieve basic common ground with their counterparts in order to ensure that accurate and efficient communication can occur at all.<br>(cont.) For certain types of higher level communication, such as skill transfer, robots need some of the underlying cognitive mechanisms that humans both possess and assume to be present in other communicative agents. One of these general mechanisms is self-awareness. This thesis details development of these underlying infrastructure components. Four broad areas of human-robot communication are then investigated, and applied to four robotic systems with different physical attributes and computational architectures. The concept of minimal communication, in which a robot must communicate basic information without the benefit of immediately recognizable anthropomorphic features, is presented. A system for enabling spatial communication, in which the human and robot must achieve common ground and support natural physical communication in the presence of other physical objects in the shared environment, is described. A model for behavioral encoding of non-verbal communication is developed, including the expression of both body language and proxemics.<br>(cont.) Finally, the use of existing communications modalities to produce interactively shaped communication for future expression is introduced, through a system that allows a human director to coach a robot through an acting performance. The robots featured in this thesis are the "Public Anemone" interactive robot theatre exhibit and "Leonardo" humanoid robot interaction testbed of the MIT Media Laboratory's Robotic Life Group; the "Robonaut" autonomous humanoid astronaut assistant robot of NASA Johnson Space Center's Dextrous Robotics Laboratory; and the "QRIO" autonomous humanoid entertainment robots of Sony Corporation's Intelligence Dynamics Laboratories.<br>by Andrew G. Brooks.<br>Ph.D.
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Torrance, Mark C. (Mark Charles). "Natural communication with robots." Thesis, Massachusetts Institute of Technology, 1994. http://hdl.handle.net/1721.1/88300.
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Glass, Abdullatif M. "Digital communication networks incorporating mobile data terminals." Thesis, Aston University, 1989. http://publications.aston.ac.uk/8086/.
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The use of digital communication systems is increasing very rapidly. This is due to lower system implementation cost compared to analogue transmission and at the same time, the ease with which several types of data sources (data, digitised speech and video, etc.) can be mixed. The emergence of packet broadcast techniques as an efficient type of multiplexing, especially with the use of contention random multiple access protocols, has led to a wide-spread application of these distributed access protocols in local area networks (LANs) and a further extension of them to radio and mobile radio communication applications. In this research, a proposal for a modified version of the distributed access contention protocol which uses the packet broadcast switching technique has been achieved. The carrier sense multiple access with collision avoidance (CSMA/CA) is found to be the most appropriate protocol which has the ability to satisfy equally the operational requirements for local area networks as well as for radio and mobile radio applications. The suggested version of the protocol is designed in a way in which all desirable features of its precedents is maintained. However, all the shortcomings are eliminated and additional features have been added to strengthen its ability to work with radio and mobile radio channels. Operational performance evaluation of the protocol has been carried out for the two types of non-persistent and slotted non-persistent, through mathematical and simulation modelling of the protocol. The results obtained from the two modelling procedures validate the accuracy of both methods, which compares favourably with its precedent protocol CSMA/CD (with collision detection). A further extension of the protocol operation has been suggested to operate with multichannel systems. Two multichannel systems based on the CSMA/CA protocol for medium access are therefore proposed. These are; the dynamic multichannel system, which is based on two types of channel selection, the random choice (RC) and the idle choice (IC), and the sequential multichannel system. The latter has been proposed in order to supress the effect of the hidden terminal, which always represents a major problem with the usage of the contention random multiple access protocols with radio and mobile radio channels. Verification of their operation performance evaluation has been carried out using mathematical modelling for the dynamic system. However, simulation modelling has been chosen for the sequential system. Both systems are found to improve system operation and fault tolerance when compared to single channel operation.
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Savci, Huseyin Serif. "Low-power CMOS receiver for medical implant communication services." Related electronic resource: Current Research at SU : database of SU dissertations, recent titles available full text, 2008. http://wwwlib.umi.com/cr/syr/main.
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Leong, Chon Chio. "Tunable defected ground structure and its applications to simultaneous reconfigurable communication and partial discharge detection." Thesis, University of Macau, 2011. http://umaclib3.umac.mo/record=b2493510.
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Pathak, Shrey. "Piezoelectric microsensors for semiochemical communication." Thesis, University of Warwick, 2012. http://wrap.warwick.ac.uk/57210/.
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Chemical communication plays vital role in the mediating the behaviour of an organism living in the “odour space”. The mechanisms by which odours are generated and detected by the organism has evolved over thousands of years and thus the potential advantages of translating this system into a fully functional communication system has opened new avenues in the area of multi-disciplinary research. This formed the basis of the Biosynthetic Infochemical Communications project – iCHEM whose central aim was to develop a new class of communication technology based on the biosynthesis pathways of the moth, S. littoralis. This novel infochemical communication system would consist of a “chemoemitter” unit which would generate a precise mix of infochemicals which after travelling through the odour space would be detected by a complementary tuned detector – the “chemoreceiver” unit comprising of a ligand specific detection element and an associated biophysical model functioning similar to the antennal lobe neuron of the moth. This combined novel system will have the capability of communicating by the help of chemicals only, in the vapour or liquid phase. For the work presented in this thesis, the novel concept of infochemical communication has been examined in the vapour and liquid phase by employing piezoelectric microsensors. This has been achieved and demonstrated throughout the thesis by employing chemo-specific acoustic wave microsensors. For vapour phase assessment, quartz crystal microbalance, were coated with different organic polymer coatings and incorporated in a prototype infochemical communication system detecting encoded volatiles. For liquid phase assessment, shear horizontal surface acoustic wave (SH-SAW) microsensors were specifically designed and immobilised within Sf9 insect cells. This GPCR based whole cell biosensing system was then employed to detect ligand specific activations thus acting as a precursor to the development of a fully functionalised OR based signalling system, thus contributing to the growing field of communication and labelling technology.
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Eltayeb, Mohammed. "Opportunistic Scheduling with Limited Feedback in Wireless Communication Networks." University of Akron / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=akron1414874159.
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Denic, Stojan. "Communication subject to normed channel uncertainties." Thesis, University of Ottawa (Canada), 2006. http://hdl.handle.net/10393/29288.
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The transmission of information over a communication channel vastly depends on the level of knowledge that a transmitter and a receiver have about the channel and the interference. The transmission of information subject to insufficient knowledge of communication environment is called communication subject to uncertainties. The goal of this thesis is twofold: (1) To introduce new models for uncertain communication channels; (2) To define, compute, and analyze the performance of communication systems subject to introduced uncertainties from an information theoretic point of view. Various communication scenarios of compound single-input single-output and multiple-input multiple-output Gaussian channels are considered. There are three main contributions of the thesis: (1) The modeling of the channel and the noise uncertainties using Hinfinity and L1 normed liner spaces in frequency domain; (2) In the case of single-input single-output channels, the channel uncertainty is modeled as a subset of H infinity space; while the noise uncertainty is modeled either by a subset of Hinfinity space or by a subset of L1 space. Explicit formulas for the channel capacities, called robust capacities, and the optimal transmitted powers in the form of new water-filling formulas, are derived that explicitly depend on the sizes of the uncertainty sets. Moreover, when the noise uncertainty is modeled by a subset of L1 space, the capacity formula has a game theoretical interpretation, where the transmitter tries to maximize the mutual information, while the noise tries to minimize it. It is shown that a saddle point exists and that the optimal PSD of the transmitter is proportional to the optimal PSD of the noise; (3) In the case of multiple input multiple-output channels, two problems are considered. When the channel uncertainty is described by a subset of Hinfinity space, it is found that the transmission over the strongest singular value of the nominal channel frequency response matrix, representing the partial channel knowledge, is optimal for a large uncertainty set. When the noise uncertainty is described by a subset of L1 space, the optimal power spectral density matrix of the noise is proportional to the optimal power spectral density matrix of the transmitted signal.
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Xu, Aoxiang 1969. "A high performance audiovisual communication system /." Thesis, McGill University, 2000. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=33352.
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The development of a communications infrastructure for the Shared Reality Environment, a high-end immersive, telepresence space, is described. Such a system must support low-latency, high fidelity, bi-directional audio and video transfer between a number of locations interconnected by an IP network.<br>As a first attempt, MJPEG video, accompanied by monaural audio was transmitted between two laboratory spaces in the McGill Centre for Intelligent Machines. The relatively high latency resulting from JPEG compression and decompression motivated a hybrid approach in which raw data was selectively transmitted whenever the overhead in doing so was less than the cost of JPEG processing.<br>Next, to scale up to the demands of transmitting multi-channel audio over greater distances, the protocol was refined and demonstrated by streaming, over the Internet, a live concert from McGill's Redpath Hall to an audience at New York University. This is believed to be the first-ever demonstration of this nature.<br>While these experiments have proven successful within the limited context of their test environment, some challenges remain to be addressed in order for the system to support the full demands of a Shared Reality immersive telepresence application.
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Mota, Joao F. C. "Communication-Efficient Algorithms For Distributed Optimization." Research Showcase @ CMU, 2013. http://repository.cmu.edu/dissertations/283.
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This thesis is concerned with the design of distributed algorithms for solving optimization problems. The particular scenario we consider is a network with P compute nodes, where each node p has exclusive access to a cost function fp. We design algorithms in which all the nodes cooperate to find the minimum of the sum of all the cost functions, f1 + · · · + fP . Several problems in signal processing, control, and machine learning can be posed as such optimization problems. Given that communication is often the most energy-consuming operation in networks and, many times, also the slowest one, it is important to design distributed algorithms with low communication requirements, that is, communication-efficient algorithms. The two main contributions of this thesis are a classification scheme for distributed optimization problems of the kind explained above and a set of corresponding communication-efficient algorithms.
The class of optimization problems we consider is quite general, since we allow that each function may depend on arbitrary components of the optimization variable, and not necessarily on all of them. In doing so, we go beyond the commonly used assumption in distributed optimization and create additional structure that can be explored to reduce the total number of communications. This structure is captured by our classification scheme, which identifies particular instances of the problem that are easier to solve. One example is the standard distributed optimization problem, in which all the functions depend on all the components of the variable.
All our algorithms are distributed in the sense that no central node coordinates the network, all the communications occur exclusively between neighboring nodes, and the data associated with each node is always processed locally. We show several applications of our algorithms, including average consensus, support vector machines, network flows, and several distributed scenarios for compressed sensing. We also propose a new framework for distributed model predictive control, which can be solved with our algorithms. Through extensive numerical experiments, we show that our algorithms outperform prior distributed algorithms in terms of communication-efficiency, even some that were specifically designed for a particular application.
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Ansari, Ashlaghi Aria. "100 GBPS Orthogonal Frequency Division Multiplexing optical fiber communication network." Thesis, California State University, Long Beach, 2015. http://pqdtopen.proquest.com/#viewpdf?dispub=1604879.
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<p> Optical fiber communication has emerged as a high potential substitute for communication methods such as twisted pair and coaxial wire. The main advantage of optical fiber over previous methods is to have higher capacity of data rate transmission. The conventional types of modulation and demodulation technique, which have been used through optical fiber communication system are Wavelength Division Multiplexing (WDM) technique and Dense Wavelength Division Multiplexing (DWDM) technique so far. </p><p> In this thesis, the Orthogonal Frequency Division Multiplexing (OFDM) is applied through the modulation and demodulation parts due to some advantages over WDM and DWDM to reach to 100 Gbps data transmission. The main advantage of OFDM-optical fiber is that it only needs one optical source to modulate and one optical source to demodulate the signals at transmitter side and receiver side, which results in a reduction of the cost of the system. Also, by using the OFDM, the chromatic dispersion can be eliminated or decreased. </p>
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Grosof, Isaac (Isaac B. ). "Secure communication : CDS, PIR, PSM." Thesis, Massachusetts Institute of Technology, 2017. http://hdl.handle.net/1721.1/113150.
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Thesis: M. Eng., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 2017.<br>This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.<br>Cataloged from student-submitted PDF version of thesis.<br>Includes bibliographical references (pages 52-53).<br>Private Information Retrieval is the problem of querying two servers to nd a value in a database, while keeping the index private. We extend this problem to Generalized Wildcard PIR, where we instead query an aggregate of the entries whose indices match a pattern, called a generalized wildcard, which species what values each segment of the indices may take. We give a construction for this variant with similar communication to that of the best PIR protocols known. We study information theoretic models in cryptography, namely Private Information Retrieval, Conditional Disclosure of Secrets, and Private Simultaneous Messages. We give extensions of PIR and CDS in the area of generalized wildcards, and give constructions for those extensions. We discuss directions towards more ecient protocols, and raise open questions.<br>by Isaac Grosof.<br>M. Eng.
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Yen, Brent J. 1977. "Multiple-user quantum optical communication." Thesis, Massachusetts Institute of Technology, 2005. http://hdl.handle.net/1721.1/30244.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2005.<br>Includes bibliographical references (p. 133-138).<br>A fundamental understanding of the information carrying capacity of optical channels requires the signal and physical channel to be modeled quantum mechanically. This thesis considers the problems of distributing multi-party quantum entanglement to distant users in a quantum communication system and determining the ability of quantum optical channels to reliably transmit information. A recent proposal for a quantum communication architecture that realizes long-distance, high-fidelity qubit teleportation is reviewed. Previous work on this communication architecture is extended in two primary ways. First, models are developed for assessing the effects of amplitude, phase, and frequency errors in the entanglement source of polarization-entangled photons, as well as fiber loss and imperfect polarization restoration, on the throughput and fidelity of the system. Second, an error model is derived for an extension of this communication architecture that allows for the production and storage of three-party entangled Greenberger-Horne-Zeilinger states. A performance analysis of the quantum communication architecture in qubit teleportation and quantum secret sharing communication protocols is presented. Recent work on determining the channel capacity of optical channels is extended in several ways. Classical capacity is derived for a class of Gaussian Bosonic channels representing the quantum version of classical colored Gaussian-noise channels. The proof is strongly motivated by the standard technique of whitening Gaussian noise used in classical information theory. Minimum output entropy problems related to these channel capacity derivations are also studied.<br>(cont.) These single-user Bosonic capacity results are extended to a multi-user scenario by deriving capacity regions for single-mode and wideband coherent-state multiple access channels. An even larger capacity region is obtained when the transmitters use non- classical Gaussian states, and an outer bound on the ultimate capacity region is presented as well.<br>by Brent J. Yen.<br>Ph.D.
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Yanco, Holly A. (Holly Ann). "Robot communication : issues and implementations." Thesis, Massachusetts Institute of Technology, 1994. http://hdl.handle.net/1721.1/37729.
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Rennie, Jason D. M. (Jason Daniel Malyutin) 1976. "Extracting information from informal communication." Thesis, Massachusetts Institute of Technology, 2007. http://hdl.handle.net/1721.1/38683.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2007.<br>Includes bibliographical references (leaves 89-93).<br>This thesis focuses on the problem of extracting information from informal communication. Textual informal communication, such as e-mail, bulletin boards and blogs, has become a vast information resource. However, such information is poorly organized and difficult for a computer to understand due to lack of editing and structure. Thus, techniques which work well for formal text, such as newspaper articles, may be considered insufficient on informal text. One focus of ours is to attempt to advance the state-of-the-art for sub-problems of the information extraction task. We make contributions to the problems of named entity extraction, co-reference resolution and context tracking. We channel our efforts toward methods which are particularly applicable to informal communication. We also consider a type of information which is somewhat unique to informal communication: preferences and opinions. Individuals often expression their opinions on products and services in such communication. Others' may read these "reviews" to try to predict their own experiences. However, humans do a poor job of aggregating and generalizing large sets of data. We develop techniques that can perform the job of predicting unobserved opinions.<br>(cont.) We address both the single-user case where information about the items is known, and the multi-user case where we can generalize opinions without external information. Experiments on large-scale rating data sets validate our approach.<br>by Jason D.M. Rennie.<br>Ph.D.
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Bourget, Marc A. (Marc Anthony) 1979. "Expanding the wireless communication paradigm." Thesis, Massachusetts Institute of Technology, 2002. http://hdl.handle.net/1721.1/87185.
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Thesis (M.Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2002.<br>"June 2002."<br>Includes bibliographical references (leaves 44-45).<br>by Marc A. Bourget.<br>M.Eng.
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Ray, Siddharth 1979. "Energy efficient multiple antenna communication." Thesis, Massachusetts Institute of Technology, 2006. http://hdl.handle.net/1721.1/38228.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2006.<br>Includes bibliographical references (leaves 111-115).<br>We consider a multiple-input, multiple-output (MIMO) wideband Rayleigh block fading channel where the channel state is unknown at the transmitter and receiver and there is only an average input power constraint. We compute the capacity and analyze its dependence on coherence length, number of antennas and receive signal-to-noise ratio (SNR) per degree of freedom. We establish conditions on the coherence length and number of antennas for the non-coherent channel to have a "near coherent" performance in the wideband regime. We also propose a signaling scheme that is near-capacity achieving in this regime. We compute the decoding error probability and study its dependence on SNR, number of antennas and coherence length. We show that error probability decays inversely with coherence length and exponentially with the product of the number of transmit and receive antennas. Moreover, in the wideband regime, channel outage dominates error probability and the critical and cut-off rates are much smaller than channel capacity. In the second part of this thesis, we introduce the concept of a fiber aided wireless network architecture (FAWNA), which allows high-speed mobile connectivity by leveraging the speed of optical networks.<br>(cont.) Specifically, we consider a single-input, multiple-output (SIMO) FAWNA, which consists of a SIMO wireless channel interfaced with an optical fiber channel through wireless-optical interfaces. We propose a design where the received wireless signal at each interface is sampled and quantized before being sent over the fiber. The capacity of our scheme approaches the capacity of the architecture, exponentially with fiber capacity. We also show that for a given fiber capacity, there is an optimal operating wireless bandwidth and number of interfaces. We show that the optimal way to divide the fiber capacity among the interfaces is to ensure that each interface gets enough rate so that its noise is dominated by front end noise rather than by quantizer distortion. We also show that rather than dynamically change rate allocation based on channel state, a less complex, fixed rate allocation scheme can be adopted with very small loss in performance.<br>by Siddharth Ray.<br>Ph.D.
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Music, Craig 1978. "Expanding the wireless communication paradigm." Thesis, Massachusetts Institute of Technology, 2002. http://hdl.handle.net/1721.1/8077.
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Gade, Sandeep. "Design and Implementation of Hybrid Hyperchaotic Sequences for Chaos-Based Communication Systems." Thesis, California State University, Long Beach, 2017. http://pqdtopen.proquest.com/#viewpdf?dispub=10638629.
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<p> Chaos-based communication piqued interest of several researchers due to the aperiodic and low cross-correlated waveforms used for modulation at the transmitter. Because of their wideband nature, they were first used as spreading sequences in traditional spread-spectrum communication systems. Later, these techniques were followed by coherent and noncoherent schemes. Noncoherent schemes unlike coherent schemes do not require chaos synchronization. </p><p> Through the years, many methods have been proposed in this category. However, increasing data rates in these schemes posed a challenge. Therefore, multidimensional signaling schemes were proposed. Orthogonal chaotic vector shift keying is one such multidimensional signaling scheme proposed by Wren and Yang. However, the chaotic system which was used to generate signaling basis in their scheme was the Lorenz system. This system forms a weak signaling basis due to the pseudo-repetitive behavior of its chaotic waveforms. Hence, the bit error rate performance of this communication scheme deteriorates in higher dimensions. In this thesis, we design and implement a hybrid hyperchaotic sequence generator for improving the performance of the orthogonal chaotic vector shift keying for higher dimensions. The analysis in this thesis is performed through computer simulations.</p><p>
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Wibowo, Henry 1966. "Communication software for telescience." Thesis, The University of Arizona, 1990. http://hdl.handle.net/10150/278227.
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This thesis presents a software development which enhances the applicability of the Operations and Science Instrument System (OASIS) software for teleoperation of scientific experiments or process plants at remote location. Software developed includes a TCP/IP communication interface for OASIS in the MicroVMS and SUN/Unix environments, and modification of previously developed software for a local controlling computer (LCC). Major improvements in software design implementation are done on the command processor task. A new software module is written for the communication part to accommodate the TCP/IP protocol which replaces the DECnet protocol. Results of comparison and measurements of both versions of OASIS are also presented.
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Rudraraju, VRS Raju. "Ultrasonic Data Communication through Petroleum." University of Akron / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=akron1271703312.
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Tsianos, Konstantinos. "The role of the network in distributed optimization algorithms: convergence rates, scalability, communication/ computation tradeoffs and communication delays." Thesis, McGill University, 2013. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=119626.
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Many questions of interest in various fields ranging from machine learning to computational biology and finance require the solution of an optimization problem. Frequently such problems are classified as large scale in the sense that they involve complex computations over very large datasets. The increasing interest in distributed optimization algorithms is motivated by two main reasons. First, the problem complexity pushes today's processors to their limits and the need for distributed algorithms arises quite naturally. A second and more practical reason is that sometimes the data is collected in a distributed manner and transmitting it to a single location is either too costly or violates privacy. The starting point of this thesis is the simple realization that the main difference between a serial and a distributed algorithm is that in the latter, a processor needs to exchange messages over a network to access another processor's information. Network communication is in general less reliable and orders of magnitude slower than local disk accesses. Furthermore, in an arbitrary network topology to achieve global performance messages might need to travel over multiple hops. Finally, the hardware's capabilities also limit the ways in which a distributed algorithm may be implemented. All these factors highlight the important role of the network in distributed optimization algorithms. To understand that role we focus on the class of consensus-based distributed optimization algorithms. Those algorithms admit an elegant theoretical analysis while remaining easy to implement. In addition they tend to be scalable and robust to communication delays. The contributions of this work can be grouped into four important areas: 1) understanding the communication/computation tradeoff and its effect on scalability with the network size, 2) understanding the limitations of the network and the necessary features that distributed algorithms need to possess to be practical, 3) understanding the effects on convergence of network-induced communication delays and 4) understanding the theoretically achievable convergence rates of distributed algorithms. These areas impact the design and deployment of any consensus-based distributed optimization algorithm.<br>Il y a une grande variété de domaines d'apprentissage automatique, de la biologie à la finance, où l'on doit résoudre des problèmes d'optimisation. Souvent ces problèmes impliquent des calculs complexes sur de vastes ensembles de données. Pour résoudre ces problèmes le développement d'algorithmes distribués est devenu très populaire pour deux raisons. Premièrement, la complexité des problèmes pousse les processeurs actuels à leurs limites. Naturellement, il devient essentiel d'utiliser des systèmes distribués. La deuxième raison est que la collecte des données est parfois distribuée, et il est difficile, coûteux ou en violation d'accords de confidentialité de transférer toutes les données au même endroit. La fondation de cette thèse est la réalisation simple que la grande différence entre un algorithme centralisé et un algorithme distribué est que ce dernier utilise un réseau pour permettre l'échange d'information d'un processeur à un autre. Généralement, la communication sur un réseau est moins fiable et beaucoup plus lente que l'accès d'information sur un disque local. De plus, pour une topologie de réseau arbitraire, la communication de messages nécessite plusieurs sauts. Finalement, les capacités matérielles aussi limitent les façons par lequelles les algorithmes distribués théoriques peuvent être mis en oeuvre. Tous ces facteurs, rappellent l'importance du réseau. Pour comprendre cette importance, nous nous concentrons, sur la classe des algorithmes de consensus pour optimisation distribuée. Ces algorithmes aussi possèdent des analyses théoriques très élégantes tout en restant faciles a mettre en oeuvre. Aussi, ils sont robustes aux délais de communication et extensibles. Les contributions de cette thèse peuvent être classifiées selon les quatres catégories suivantes: 1) comprendre le compromis entre communication et calculs locaux, et l'extensibilité avec la taille du réseau, 2) comprendre les limites posées par le réseau aux fonctionnalités nécessaires que chaque algorithme distribué doit possèder en pratique, 3) comprendre les effets de délais de communication et les propriétés de convergence de ces algorithmes en présence de délais, 4) comprendre les taux théoriques de convergence des algorithmes d'optimisation distribués. Tous ces domaines affectent la conception et le déploiement de chaque algorithme de consensus d'optimisation distribué.
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Shah, Chintan Hemendra. "Inductively Coupled Interconnect for Chip to Chip Communication over Transmission Line." NCSU, 2009. http://www.lib.ncsu.edu/theses/available/etd-04012009-003531/.
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As data frequency increases beyond several Gbps range, low power chip to chip communication becomes more critical. The concept researched in this thesis is inductively coupled interconnect (LCI) over short length transmission line. The data will be transmitted across a 10 cm differential microstrip line on FR-4 material with a transformer on each side of the line. The transmitter and receiver circuits are designed in TSMC 0.18μm process technology and can operate at 2.5 Gbps. The power consumption of the design is 5.53 mW at 2.5 Gbps which yields around 2.21 mW.Gb-1.s-1. This design can achieve BER of less than 10-12. The inductive coupling will reduce DC power because the low frequency DC component of the signal will be blocked by coupling inductors. The power consumed by this design is lower than most of the conventional I/Os that use physical contact interconnects. An H-bridge current steering driver is used at the transmitter and a differential amplifier and Sense-amp Flip flop is used at the receiver.
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Dávila, García Francisco Javier. "A power efficient active RFID communication Protocol." Thesis, Jönköping University, JTH, Computer and Electrical Engineering, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:hj:diva-1033.
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<p>Active Radio Frequency Identification (Active RFID) is a wireless automated technology used to identify, track, process and share information about an object or from the environment. As microcontrollers and radio frequency transponders are smaller in size, more power efficient, and less expensive, this technology is growing and starting to expand significantly through all the industries. The main purpose of with this project was to reduce the ower consumption of the active tags. This master thesis presents a functional TDMA based protocol which was designed and developed for a specific tracking system application.</p>
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Mheidat, Hakam. "Channel Estimation and Equalization for Cooperative Communication." Thesis, University of Waterloo, 2006. http://hdl.handle.net/10012/2852.
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The revolutionary concept of space-time coding introduced in the last decade has demonstrated that the deployment of multiple antennas at the transmitter allows for simultaneous increase in throughput and reliability because of the additional degrees of freedom offered by the spatial dimension of the wireless channel. However, the use of antenna arrays is not practical for deployment in some practical scenarios, e. g. , sensor networks, due to space and power limitations. <br /><br /> A new form of realizing transmit diversity has been recently introduced under the name of user cooperation or cooperative diversity. The basic idea behind cooperative diversity rests on the observation that in a wireless environment, the signal transmitted by the source node is overheard by other nodes, which can be defined as "partners" or "relays". The source and its partners can jointly process and transmit their information, creating a "virtual antenna array" and therefore emulating transmit diversity. <br /><br /> Most of the ongoing research efforts in cooperative diversity assume frequency flat channels with perfect channel knowledge. However, in practical scenarios, e. g. broadband wireless networks, these assumptions do not apply. Frequency-selective fading and imperfect channel knowledge should be considered as a more realistic channel model. The development of equalization and channel estimation algorithms play a crucial element in the design of digital receivers as their accuracy determine the overall performance. <br /><br /> This dissertation creates a framework for designing and analyzing various time and frequency domain equalization schemes, i. e. distributed time reversal (D-TR) STBC, distributed single carrier frequency domain (D-SC-FDE) STBC, and distributed orthogonal frequency division multiplexing (D-OFDM) STBC schemes, for broadband cooperative communication systems. Exploiting the orthogonally embedded in D-STBCs, we were able to maintain low-decoding complexity for all underlying schemes, thus, making them excellent candidates for practical scenarios, such as multi-media broadband communication systems. <br /><br /> Furthermore, we propose and analyze various non-coherent and channel estimation algorithms to improve the quality and reliability of wireless communication networks. Specifically, we derive a non-coherent decoding rule which can be implemented in practice by a Viterbi-type algorithm. We demonstrate through the derivation of a pairwise error probability expression that the proposed non-coherent detector guarantees full diversity. Although this decoding rule has been derived assuming quasi-static channels, its inherent channel tracking capability allows its deployment over time-varying channels with a promising performance as a sub-optimal solution. As a possible alternative to non-coherent detection, we also investigate the performance of mismatched-coherent receiver, i. e. , coherent detection with imperfect channel estimation. Our performance analysis demonstrates that the mismatched-coherent receiver is able to collect the full diversity as its non-coherent competitor over quasi-static channels. <br /><br /> Finally, we investigate and analyze the effect of multiple antennas deployment at the cooperating terminals assuming different relaying techniques. We derive pairwise error probability expressions quantifying analytically the impact of multiple antenna deployment at the source, relay and/or destination terminals on the diversity order for each of the relaying methods under consideration.
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Goulet, Laurent. "Turbo decoding for transmit diversity communication systems." Thesis, McGill University, 2001. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=33969.
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This thesis considers a combination of iterative decoding with space-time coding, known as space-time-turbo coding. Parallel and serial concatenated codes are considered for transmission using different bandwidth allocation schemes.<br>The analysis of space-time-turbo codes is then performed in this thesis, resulting in the derivation of code design rules and of performance bounds. In particular, epsilon-capacity curves (based on the outage probability) are seen to provide a visually attractive method for the evaluation of the bandwidth-efficiency/performance tradeoff achieved by different codes. Computer simulations are then used to evaluate the performance of the proposed space-time-turbo codes over the spatially-uncorrelated block Rayleigh fading channel. It is then seen that certain space-time-turbo codes can outperform other recently proposed space-time codes.<br>Finally, in light of simulation results, a low-complexity serial concatenated code is presented. This scheme, making use of a Wyner-Ash outer code and an inner recursive convolutional code achieving full-diversity, is shown to provide a good tradeoff between bandwidth-efficiency and error rate performance over the spatially-uncorrelated quasi-static Rayleigh fading channel.
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Radji, Djelili. "Asymptotic optimal detection for MIMO communication systems." Thesis, McGill University, 2014. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=121110.
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The high complexity of optimal detection for spatial multiplexing MIMO systems motivates the need for more practical alternatives. Among many suboptimal schemes reported in the literature, very few can be proven to provide close to optimal performance with low fixed complexity. In this thesis, we consider a class of list-based detectors that first generate a list of candidate decision vectors, and then the best candidate in the list is chosen as the final decision. First, we perform a diversity analysis of such schemes and derive sufficient conditions for achieving optimal performance asymptotically. We then introduce the Sel-MMSE-OSIC algorithm that employs list-based detection and a diversity maximizing channel partition procedure that yields asymptotic optimality. Then we propose the MMSE-ISTP scheme which is an improved asymptotically optimal fixed complexity algorithm that provides substantial complexity reductions over Sel-MMSE-OSIC. This scheme is based on simplified channel partition and efficient tree based list detection. Simulations results show that Sel-MMSE-OSIC and MMSE-ISTP yield performances that are nearly indistinguishable from optimal at almost all SNR levels for space uncorrelated systems. To achieve further reductions in complexity for large constellation sizes, a variable complexity version of the MMSE-ISTP scheme is proposed. The resulting algorithm is a variable complexity scheme that operates on a very small subset of candidates, and employs an improved channel partition preprocessing that not only reduces complexity but also guarantees high SNR optimality over space uncorrelated channels. Simulations results confirm that the proposed scheme provides significant complexity reductions over conventional variable complexity detection schemes.<br>La haute complexité associée à la méthode optimale de détection pour les systèmes MIMO utilisant le multiplexage spatial motive la recherche d'alternatives plus pratiques. Parmi les nombreuses méthodes non optimales proposées dans la littérature, très peu peuvent théoriquement guarantir une performance quasi-optimale avec une complexité fixe et relativement basse. Dans cette thèse, nous considérons une classe de détecteurs utilisant une liste, qui premièrement génèrent une liste de vecteurs candidats et ensuite choisissent le meilleur candidat dans cette liste comme décision finale. Dans un premier temps nous faisons une analyse de diversité pour ces méthodes et dérivons des conditions suffisantes pour atteindre asymptotiquement une performance optimale. Nous introduisons ensuite l'algorithme Sel-MMSE-OSIC qui emploie une méthode de détection utilisant une liste et une méthode de partition du canal à diversité maximale permettant l'optimalité asymptotique. Après, nous proposons l'algorithme MMSE-ISTP qui apporte des réductions substantielles de complexité comparé à l'algorithme Sel-MMSE-OSIC tout en ayant une complexité fixe et étant asymptotiquement optimal. Cette méthode est basée sur une simplification de la partition du canal et une méthode de détection efficace utilisant une liste générée à partir d'un arbre de détection. Les résultats des simulations par ordinateur démontrent que Sel-MMSE-OSIC et MMSE-ISTP délivrent des performances pratiquement indissociables de la performance optimale pour tous les rapports signal-sur-bruit pour des canaux non corrélés dans l'espace. Pour atteindre des reductions additionnelles de complexité pour les grandes constellations, une version de MMSE-ISTP à complexité variable est ensuite proposée. L'algorithme qui en résulte est un algorithme à complexité variable qui opère sur un nombre réduit de candidats et emploie une méthode de partition du canal améliorée qui non seulement réduit la complexité mais aussi guarantit l'optimalité pour des rapports signal-sur-bruit élevés pour des canaux non corrélés dans l'espace. Les résultats des simulations par ordinateur confirment que l'algorithme proposé permet des réductions significatives de la complexité comparé aux techniques à complexité variable conventionnelles.
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Camack, Matt Marcus. "Systems Engineering Analysis and Digital Communication Bus Design for the Cal Poly SuPER Project." DigitalCommons@CalPoly, 2010. https://digitalcommons.calpoly.edu/theses/298.
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With an expected lifetime of 20 years and an expected cost of $500, the Cal Poly Sustainable Power for Electrical Resources (SuPER) project needed a strong central design. This thesis looks at the work completed by students over the previous 5 years, with an eye on the future, to create the phase 2 design. Part of this new structure focuses on a distributed communication bus for monitoring system health and status. Instead of complex and costly computer or FPGA systems, the new system will run solely with microcontrollers. This reduces costs and will hopefully still be used within 5, 10, and 20 years as the number of embedded devices continues to grow globally. The new system design was created using many systems engineering tools and benchmarks, including: requirements breakdown, hardware interfacing, software interfacing, safety, reliability, maintainability, and cost. Major components have been broken down into subsystems with well-defined requirements for implementation. These smaller projects can be completed by future team members as senior projects, independent work, or even Master’s theses. Upon test and integration, these subsystems will come together into a field-ready model to help bring power to the two billion people on Earth lacking it.
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Muralidharan, Sreraman. "Architectures for long distance quantum communication." Thesis, Yale University, 2018. http://pqdtopen.proquest.com/#viewpdf?dispub=10783458.
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<p> Despite the tremendous progress of quantum cryptography, efficient quantum communication over long distances (≥ 1000km) remains an outstanding challenge due to fiber attenuation and operation errors accumulated over the entire communication distance. Quantum repeaters (QRs), as a promising approach, can overcome both photon loss and operation errors, and hence significantly speedup the communication rate. Depending on the methods used to correct loss and operation errors, all the proposed QR schemes can be classified into three categories (generations). First generation QRs use heralded entanglement generation for the correction of erasure errors and entanglement purification for the correction of operation errors. Second generation QRs use heralded entanglement generation for the correction of erasure errors and quantum error correction for the correction of operation errors. third-generation QRs use quantum error correction for the correction of both erasure and operation errors respectively. It is important to develop robust protocols for quantum repeaters, and systematically compare the performance of various QRs.</p><p> We investigate the use of efficient error correcting codes for third-generation QRs that make use of small encoding blocks to fault-tolerantly correct both loss and operation errors. Our schemes use quantum parity codes. quantum polynomial codes and quantum Reed-Solomon codes for encoding quantum information and use teleportation-based error correction to systematically correct erasure and operation errors in a fault-tolerant manner. We describe a way to optimize the resource requirements and system parameters for these QRs with the aim of generating a secure key. We perform a systematic comparison among these codes and identify the parameter regimes of operation errors where each code performs the best.</p><p> We then perform a systematic comparison of the three generations of QRs by evaluating the cost of both temporal and physical resources, and identify the optimized QR architecture for a given set of experimental parameters. Our work provides a roadmap for the experimental realization of highly efficient quantum networks over transcontinental distances.</p><p>
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Qian, Xinben Garrison. "Adaptive systems in digital communication designs." Thesis, Massachusetts Institute of Technology, 1996. http://hdl.handle.net/1721.1/38821.
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Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1996.<br>Includes bibliographical references (leaves 98-100).<br>by Xinben Garrison Qian.<br>M.S.
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Jagabathula, Srikanth. "Scheduling algorithms for arbitrary communication networks." Thesis, Massachusetts Institute of Technology, 2008. http://hdl.handle.net/1721.1/44450.
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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2008.<br>Includes bibliographical references (p. 89-91).<br>We consider the problem of designing scheduling schemes for networks with arbitrary topology and scheduling constraints. We address the optimality of scheduling schemes for packet networks in terms of throughput, delay and fairness. Specifically, we design two scheduling schemes. The first one achieves simultaneous throughput and delay optimization. The second scheme provides fairness. We design a scheduling scheme that guarantees a per-flow average delay bound of O(number of hops), with a constant factor loss of throughput. We derive the constants for a network operating under primary interference constraints. Our scheme guarantees an average delay bound of ... is the number of hops and pj is the effective loading along flow j. This delay guarantee comes at a factor 5 loss of throughput. We also provide a counter-example to prove the essential optimality of our result. For the fair scheduling scheme, we define a packet-based notion of fairness by establishing a novel analogy with the ranked election problem. The election scheme of Goodman and Markowitz (1952) [14] yields a maximum weight style scheduling algorithm. We then prove the throughput optimality of the scheme for a single-hop network. Standard methods for proving the stability of queuing systems fail us and hence we introduce a non-standard proof technique with potential wider applications.<br>by Srikanth Jagabathula.<br>S.M.
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Henry, Dana S. (Dana Sue). "Hardware mechanisms for efficient interprocessor communication." Thesis, Massachusetts Institute of Technology, 1996. http://hdl.handle.net/1721.1/11290.
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Beal, Jacob Stuart Michael. "Generating communication systems through shared context." Thesis, Massachusetts Institute of Technology, 2002. http://hdl.handle.net/1721.1/87194.
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Gu, Yuzhou. "Zero-error communication over adder MAC." Thesis, Massachusetts Institute of Technology, 2018. http://hdl.handle.net/1721.1/120387.
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Thesis: M. Eng., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 2018.<br>This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.<br>Cataloged from student-submitted PDF version of thesis.<br>Includes bibliographical references (pages 53-54).<br>Adder MAC is a simple noiseless multiple-access channel (MAC), where if users send messages X₁, . . . ,X[subscript h] [epsilon] {0, 1}[superscript n], then the receiver receives Y = X₁ + · · · + X[subscript h] with addition over Z. Communication over the noiseless adder MAC has been studied for more than fifty years. There are two models of particular interest: uniquely decodable code tuples, and B[subscript h]-codes. In spite of the similarities between these two models, lower bounds and upper bounds of the optimal sum rate of uniquely decodable code tuple asymptotically match as number of users goes to infinity, while there is a gap of factor two between lower bounds and upper bounds of the optimal rate of B[subscript h]-codes. The best currently known B[subscript h]-codes for h >/- 3 are constructed using random coding. In this thesis, we study variants of the random coding method and related problems, in hope of achieving B[subscript h]-codes with better rate. Our contribution include the following. 1. We determine the rate achieved by changing the underlying distribution used in random coding. 2. We determine the rate of a list-decoding version of B[subscript h]-codes achieved by the random coding method. 3. We study several related problems about Rényi entropy.<br>by Yuzhou Gu.<br>M. Eng.
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Min, Rex K. (Rex Kee) 1976. "Energy and quality scalable wireless communication." Thesis, Massachusetts Institute of Technology, 2003. http://hdl.handle.net/1721.1/28272.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2003.<br>Includes bibliographical references (p. 165-171).<br>Nodes for emerging, high-density wireless networks will face the dual challenges of continuous, multi-year operation under diverse and challenging operating conditions. The wireless communication subsystem, a substantial consumer of energy, must therefore be designed with unprecedented energy efficiency. To meet this challenge, inefficiencies once overlooked must be addressed, and the system must be designed for energy scalability, the use of graceful energy vs. quality trade-offs in response to continuous variations in operational conditions. Using a comprehensive model framework that unifies cross-disciplinary models for energy consumption and communication performance, this work explores multi-dimensional trade-offs of energy and quality for wireless communication at all levels of the system hierarchy. The circuit-level "knob" of dynamic voltage scaling is implemented on a commercial microprocessor and integrated into a power aware, prototype microsensor node. Power aware abstractions encourage collaboration between the hardware, which fundamentally dissipates the energy, and software, which controls how the hardware behaves. Accurate models of hardware energy consumption reveal inefficiencies of routing techniques such as multihop, and the models are fused with information-theoretic limits on code performance to bound the energy scalability of the hardware platform. An application-specific protocol for microsensor networks is evaluated with a new, interactive Java simulation tool created expressly for energy-conscious, high density wireless networks. Close collaboration between software and hardware layers, and across the research disciplines that compose wireless communication itself, are crucial enablers for energy-efficient wireless communication.<br>by Rex Kee Min.<br>Ph.D.