Forward error correction (FEC) is as one of the key technologies enabling the next-generation high-speed fiber optical communications. In this paper, we propose a rate-adaptive scheme using a class of generalized low-density parity-check (GLDPC) codes with a Hamming code as local code. We show that with the proposed unified GLDPC decoder architecture, a variable net coding gains (NCGs) can be achieved with no error floor at BER down to 10(-15), making it a viable solution in the next-generation high-speed fiber optical communications.

Abstract Handoff is the procedure providing the connection to the backbone network while a mobile terminal is moving across the boundaries of coverage of two wireless points of connection. The complexity of the handoff decision process has led to the examination of a number of traditional and pattern recognition handoff decision algorithms for wireless networks. Traditional algorithms use a received signal strength measurement and an optional threshold, hysteresis, or a dwell timer to determine the handoff decision. Degradation of the signal level, however, is a random process, and simple decision mechanisms result in a ping–pong effect whereby several consecutive handoffs degrade the service provided by the network. Consequently, more complex pattern recognition algorithms are needed to decide on the optimal time for handoff. In these algorithms, the handoff decision receives off line training to create a reference database of possible handoff locations in an environment with an associated handoff "fingerprint" at those locations. This dissertation introduces newly designed neural network and adaptive network based fuzzy inference system (ANFIS) pattern recognition algorithms. To select appropriate algorithms for a specific wireless network, we need to create an analytical framework for performance evaluation. The design of a framework for comparative performance evaluation of different handoff algorithms is a complex problem as different networks have different performance evaluation criteria. This dissertation divides wireless networks into three categories according to their topology and wireless service application: traditional cellular phone networks, heterogeneous wireless data networks, and rate adaptive wireless data networks. For each category of wireless networks we define a performance evaluation scenario and using Monte Carlo simulations, Monte Carlo calculations, and direct mathematical analysis we analyze the effects of different handoff decision algorithms. The Manhattan micro-cellular scenario is used for traditional cellular phone networks. Using Monte Carlo simulations on this scenario, the performance of traditional and our neural network and ANFIS handoff decision algorithms are compared. A moving-in moving-out performance evaluation scenario for heterogeneous wireless data networks is defined to characterize intertechnology roaming between two networks with substantially different data rates. We use Monte Carlo calculations to define the optimum handoff location for a mobile terminal in this scenario. Using Monte Carlo simulations and the optimal handoff location, we perform comparative performance evaluation of newly introduced asymmetric traditional and pattern recognition algorithms designed for intertechnology handoff. Finally, we introduce two performance evaluation scenarios for rate adaptive wireless networks to characterize user mobility in rate adaptive networks with random and grid deployments. For the first scenario we provide mathematical analysis for the effects of handoff using relative power to calculate the average throughput observed by the mobile terminal for different distances between the two wireless points of connection. For the second scenario designed for grid deployment we present a comparative performance analysis using Monte Carlo calculations for four handoff decision algorithms.

<p>Free-space optical (FSO) communication has witnessed rapid development recently in response to ever-increasing demands for greater bandwidth. FSO links provide fiberspeed with the flexibility of wireless. Commercially available systems offer transmission speeds up to 2.5 Gbps, 5 Gbps and 10 Gbps, and demonstration systems report data rates as high as 160 Gbps. Its advantages also include license free operation, high immunity to interference, and ease of deployment. However, FSO systems are sensitive to adverse weather conditions such as fog, rain and snow.</p> <p>In order to improve the availability of FSO channels degraded by atmospheric turbulence and varying weather conditions, the effects of channel gain variations must be compensated. In this thesis, two rate-adaptive techniques, punctured low-density parity-check (LDPC) codes and Raptor codes, are studied using experimental data measured over a1.87 km terrestrial FSO link.</p> <p>Rate-adaptive performances with punctured LDPC codes and Raptor codes are evaluated in terms of outage probability and throughput. In comparison to uncoded system, rate-adaptive systems with both techniques demonstrate significant improvement of throughput and mitigation of outage probability especially in rainy weather. Due to its flexible rate-adaptation and simple hardware implementation, Raptor coded systems are judged more applicable to be implemented in field-programmable gate array (FPGA) based hardware. A dedicated decoding structure is proposed and tested, showing remarkable improvement in resource efficiency as compared to traditional Gauss-Jordan (GJ) decoding structures.</p> / Master of Applied Science (MASc)

International Telemetering Conference Proceedings / October 23-26, 2000 / Town & Country Hotel and Conference Center, San Diego, California / This paper introduces new telemetry equipment based on Digital Subscriber Loop DSL technology (high speed transmission over copper cables) for military and industrial applications. A brief xDSL technology overview is followed with introduction of the new ‘P3’ product. A number of new applications for remote data transmission are presented and further highlighted in the Australian Army report detailing their recent equipment operational deployments.

International Telemetering Conference Proceedings / October 22-25, 2001 / Riviera Hotel and Convention Center, Las Vegas, Nevada / This paper introduces new telemetry (communications) equipment based on Digital Subscriber Loop DSL technology (high speed transmission over copper cables) for defense and industrial applications. A brief xDSL technology overview is followed with introduction of the new ‘P3’ product and its application, reviewing advantages of using copper as a communications medium whenever rapidly deployed data and voice links are essential. An Australian Army report, detailing a specific equipment deployment’s findings is reproduced as an independent reference material.

Mikroprozessorgesteuerte Implantate haben sich in zahlreichen Bereichen der Medizin etabliert. Physiologische, korpereigene Parameter werden erfasst, abgespeichert und konnen durch Telemetriesysteme weitergeleitet werden. Zusatzlich stehen Therapieoptionen zur Verfugung. Dazu zahlen Neurostimulatoren, welche im Bereich der Schmerztherapie und des fortgeschrittenen Morbus Parkinson erfolgreich angewendet werden ebenso wie Systeme zur Medikamentenapplikation. Beispielhaft hat sich die Entwicklung aktiver Implantate jedoch im Bereich der Herzschrittmacher- und Defibrillatortherapie vollzogen. Die vorliegende Arbeit beschaftigt sich mit der Erforschung physiologischer kardialer Parameter und ihrer Erfassung mit Hilfe von implantierbaren Sensoren. Dabei werden grundlegende technische Aspekte, die spezielle Sensorik zur Erfassung verschiedener Parameter und die Signalverarbeitung dargestellt. Es werden die bereits heute vielfaltigen Moglichkeiten implantierbarer kardialer Monitoringsysteme diskutiert. Neue Moglichkeiten wie das Monitoring ischamischer Ereignisse werden eroffnet. / Mikroprocessor controlled implantable systems are standard in many medical specialities. Physiological parameters can be recorded, stored and transfered via telemetry systems. In addition different therapeutic options are available: neurostimulation to treat patients with refractory pain and morbus parkinson, drug pumps for infusion of insulin etc.. Cardiac pacemakers and implantable cardioverter defibrillators were the driving force in the development of implantable sensors. We investigated different physiological cardiac parameters via implantable sensors. In this paper we discuss basic technical aspects, sensors, signal conditioning and signal analysis. The spectrum of available implantable sensors is shown. New options like the monitoring of transient myocardial ischemia are presented.

In radar target tracking problems, it may be required to use adaptive update rate in order to maintain the tracking accuracy while allowing the radar to use its resources economically at the same time. This is generally the case if the target trajectory has maneuvering segments and in such a case the use of adaptive update time interval algorithms for estimation of the target state may enhance the tracking accuracy. Conventionally, fixed track update time interval is used in radar target tracking due to the traditional nature of mechanically steerable radars. In this thesis, as an application to phased array radar, the adaptive update rate algorithm approach developed in literature for Alpha-Beta filter is extended to Kalman filter. A survey over relevant adaptive update rate algorithms used previously in literature on radar target tracking is presented including aspects related to the flexibility of these algorithms for the tracking filter. The investigation of the adaptive update rate algorithms is carried out for the Kalman filter for the single target tracking problem where the target has a 90&deg / maneuvering segment in its trajectory. In this trajectory, the starting and final time instants of the single maneuver are specified clearly, which is important in the assessment of the algorithm performances. The effects of incorporating the variable update time interval into target tracking problem are presented and compared for several different test cases.

The proliferation of new devices (such as smartphones and tablets) promotes new multimedia services (e.g. user-generated live video broadcasting), as well as new streaming techniques (e.g. rate-adaptive streaming). As a matter of fact, scientists observe a formidable, sustainable growth of Internet traffic related to video streaming. Yet, network infrastructures struggle to cope with this growth and it is now frequent that a delivery network is insufficiently provisioned. Such underprovisioning problem is more severe for live videos due to its real-time requirement. In this thesis, we focus on bandwidth efficient video delivery solutions for live streaming in underprovisioned video delivery networks. Specifically, we have two main contributions: (1) a user-generated live videos sharing system based on peer-to-peer (P2P) technique, and (2) a live rate-adaptive streaming system based on Content Delivery Network (CDN). First of all, we built an multioverlay P2P video sharing system which allows Internet users to broadcast their own live videos. Typically, such a system consists of multiple P2P live video streaming systems, and faces the problem of finding a suitable allocation of peer upload bandwidth. We designed various bandwidth allocation algorithms for this problem and showed how optimal solutions can be efficiently computed. Then, we studied the problem of delivering live rate-adaptive streams in the CDN. We identified a discretize streaming model for multiple live videos in modern CDNs. We formulated a general optimization problem through Integer Linear Programming (ILP) and showed that it is NP-complete. Further, we presented a fast, easy to implement, and near-optimal algorithm with approved approximation ratios for a specific scenario. This work is the first step towards streaming multiple live rate-adaptive videos in CDN and provides a fundamental theoretical basis for deeper investigation. Last, we further extended the discretized streaming model into an user-centric one which maximizes the overall satisfaction of an user population. Further, we presented a practical system, which efficiently utilizes CDN infrastructure to deliver live video streams to viewers in dynamic and large-scale CDNs. The benefits of our approaches on reducing the CDN infrastructure capacity is validated through a set of realistic trace-driven large-scale simulations. All in one, this thesis explores bandwidth efficient live video delivery solutions in underprovisioned delivery network for multiple streaming technologies. The aim is to maximally utilize the bandwidth of relay nodes (peers in P2P and forwarding equipments in CDN) to achieve an optimization goal.

Opportunistic selection is a practically appealing technique that is often used in multi-node wireless systems such as scheduling and rate adaptation in cellular systems and opportunistic wireless local area networks, wireless sensor networks, cooperative communications, and vehicular networks. In it, each node maintains a local preference number called metric that is function of its channel gains, and the best node with the highest metric is selected. Identifying the best node is challenging as the information about a node's metric is available only locally at each node. In our work, we focus on the popular, simple, and low feedback timer scheme for selection. In it, each node sets a timer as a function of its metric and transmits a packet when the timer expires. The metric-to-timer mapping maps larger metric values to smaller timer values, which ensures that the best node's timer expires first. However, it can fail to select the best node if another node transmits a packet within D s of the transmission by the best node. In this thesis, we make three contributions to the design and understanding of the timer-based selection scheme. Firstly, we introduce feedback overhead-aware contention resolution in the timer-based selection scheme. The outcome is a novel selection scheme that is faster than the splitting scheme and more reliable than the timer-based selection scheme. We analyze and minimize the average time required by the scheme to select the best node. Secondly, we characterize the optimal metric-to-timer mapping when the number of nodes in the system is not known, as is the case in several practical deployments. When the prior distribution of the nodes is known, we propose an optimal mapping that maximizes the success probability averaged over the distribution on the number of nodes. When even the prior distribution is not known, we propose a robust mapping that maximizes the worst case average success probability over all possible probability distributions on the number of nodes. In both cases, we show that the timers can expire only at 0, D, 2D, ... in the optimal timer mapping. For the known prior case, we develop recursive techniques to effectively compute the optimal timer mapping for binomial and Poisson priors. Lastly, we consider a discrete rate adaptive system and design an optimal timer scheme to maximize the end-to-end performance measure of system throughput. We derive several novel, insightful results about the optimal mapping that culminate in an iterative algorithm to compute it. We show that the design of the selection scheme is intimately related to the rate adaptation rule and the selection policy used. In all cases, extensive benchmarking with several ad hoc schemes proposed in the literature shows the significant gains that the proposed designs can deliver.

[pt] A comunicação por fibras ópticas utiliza diversos modelos herdados dos sistemas de telecomunicações tradicionais. Recentemente, a necessidade de maior controle sobre o fluxo de dados tem atraído muita atenção para as vantagens da comunicação óptica adaptativa. Num sistema de comunicação adaptativo, o fluxo de dados pode ser alterado em função de variações na qualidade do canal ou simplesmente pela necessidade de racionalizar a utilização dos recursos disponíveis. A interoperação entre redes pressiona pela necessidade de uma rede elástica e a expectativa é que este tipo de rede permita o controle sobre vários níveis da estrutura de comunicação. Nesta tese, a análise deste tema se concentra na camada física da rede óptica, em que a elasticidade pode ser obtida através de diferentes técnicas de modulação e multiplexação. A camada física de uma rede óptica adaptativa deve responder a variações e restrições do meio de transmissão. O consumo de energia, por exemplo, é um requisito cada vez mais presente nos projetos das redes de comunicação e a relevância deste requisito tende a aumentar na medida em que as redes ópticas aumentam sua capilaridade. O principal objetivo desta tese é analisar uma solução de comunicação óptica adaptativa que atenda aos requisitos básicos de uma rede elástica. O sistema de comunicação em análise é baseado em modulações realizadas no espaço de sinais de quatro dimensões, também conhecidas como modulações 4D. A perspectiva adotada privilegia a polarização da portadora óptica. A vantagem em adotar esta perspectiva, reside no fato de que ela permite a construção de modulações multidimensionais utilizando os fibrados de Hopf. Conforme será observado, o uso dos fibrados de Hopf em conjunto com o conceito matemático denominado vértice embutido de politopos, potencializa as soluções de engenharia para o problema da comunicação óptica adaptativa. / [en] Fiber-optic communications use several models inherited from traditional telecommunications systems. Recently, the need to improve the control over the data flow has attracted attention to the advantages of adaptive optical communication. In adaptive systems, the data flow can be altered due to changes in the channel quality or simply to rationalize the use of available resources. Interoperation between networks further presses on the need for an elastic network and the expectation is that this type of network will allow control over various levels of the communication structure. In this thesis, the analysis of this theme focuses on the physical layer of the optical network, where elasticity can be obtained through different modulation and multiplexing techniques. The physical layer of an adaptive optical network must respond to variations and restrictions of the transmission medium. Energy consumption, for example, is a requirement that is increasingly present in communication network projects and the relevance of this requirement tends to increase as optical networks expands in capillarity. The main objective of this thesis is to analyze an adaptive optical communication solution that meets the basic requirements of an elastic network. The communication system under analysis is based on the four-dimensional signal space modulations, also known as 4D modulations. The perspective adopted favors the polarization of the optical carrier. The advantage in adopting this perspective resides in the fact that it allows the construction of multidimensional modulations using Hopf bundles. As will be observed, the use of Hopf bundles in conjunction with the mathematical concept called embedded vertex polytopes, improves the engineering solutions to the problem of adaptive optical communication.