Review of Recent Trends

This work was partially supported by the European Regional Development Fund (FEDER), through the Regional Operational Programme of Centre (CENTRO 2020) of the Portugal 2020 framework, through projects SOCA (CENTRO-01-0145-FEDER-000010) and ORCIP (CENTRO-01-0145-FEDER-022141). Fernando P. Guiomar acknowledges a fellowship from “la Caixa” Foundation (ID100010434), code LCF/BQ/PR20/11770015. Houda Harkat acknowledges the financial support of the Programmatic Financing of the CTS R&D Unit (UIDP/00066/2020).MIMO-OFDM is a key technology and a strong candidate for 5G telecommunication systems. In the literature, there is no convenient survey study that rounds up all the necessary points to be investigated concerning such systems. The current deeper review paper inspects and interprets the state of the art and addresses several research axes related to MIMO-OFDM systems. Two topics have received special attention: MIMO waveforms and MIMO-OFDM channel estimation. The existing MIMO hardware and software innovations, in addition to the MIMO-OFDM equalization techniques, are discussed concisely. In the literature, only a few authors have discussed the MIMO channel estimation and modeling problems for a variety of MIMO systems. However, to the best of our knowledge, there has been until now no review paper specifically discussing the recent works concerning channel estimation and the equalization process for MIMO-OFDM systems. Hence, the current work focuses on analyzing the recently used algorithms in the field, which could be a rich reference for researchers. Moreover, some research perspectives are identified.publishersversionpublishe

Design of reliable and energy-efficient high-speed interface circuits

The data-rate demand in high-speed interface circuits increases exponentially every year. High-speed I/Os are better implemented in advanced process technologies for lower-power systems, with the advantages of improved driving capability of the transistors and reduced parasitic capacitance. However, advanced technologies are not necessarily advantageous in terms of device reliability; in particular device failure from electrostatic discharge (ESD) becomes more likely in nano-scale process nodes. In order to secure ESD resiliency, the size of ESD devices on I/O pads should be sufficiently large, which may potentially reduce I/O speed. These two conflicting requirements in high-speed I/O design sometimes require sacrifice to one of the two properties. In this dissertation, three different approaches are proposed to achieve reliable and energy-efficient interface circuits. As the first approach, a novel ESD self-protection scheme to utilize “adaptive active bias conditioning” is proposed to reduce voltage stress on the vulnerable transistors, thereby reducing the burden on ESD protection devices. The second approach is to cancel out effective parasitic capacitance from ESD devices by the T-coil network. Voltage overshoot generated by magnetic coupling of the T-coil network can be suppressed by the proposed “inductance halving” technique, which reduces mutual inductance during ESD. The last approach employs system-level knowledge in the design of an ADC-based receiver for high intersymbol interference (ISI) channels. As a system-level performance metric, bit-error rate (BER) is adopted to mitigate a bit-resolution requirement in “BER-optimal ADC”, which can lead to 2× power-efficiency in the flash ADC and achieve a better BER performance

Recent Advances in Wireless Communications and Networks

This book focuses on the current hottest issues from the lowest layers to the upper layers of wireless communication networks and provides "real-time" research progress on these issues. The authors have made every effort to systematically organize the information on these topics to make it easily accessible to readers of any level. This book also maintains the balance between current research results and their theoretical support. In this book, a variety of novel techniques in wireless communications and networks are investigated. The authors attempt to present these topics in detail. Insightful and reader-friendly descriptions are presented to nourish readers of any level, from practicing and knowledgeable communication engineers to beginning or professional researchers. All interested readers can easily find noteworthy materials in much greater detail than in previous publications and in the references cited in these chapters

Channel Coding in Molecular Communication

This dissertation establishes and analyzes a complete molecular transmission system from a communication engineering perspective. Its focus is on diffusion-based molecular communication in an unbounded three-dimensional fluid medium. As a basis for the investigation of transmission algorithms, an equivalent discrete-time channel model (EDTCM) is developed and the characterization of the channel is described by an analytical derivation, a random walk based simulation, a trained artificial neural network (ANN), and a proof of concept testbed setup. The investigated transmission algorithms cover modulation schemes at the transmitter side, as well as channel equalizers and detectors at the receiver side. In addition to the evaluation of state-of-the-art techniques and the introduction of orthogonal frequency-division multiplexing (OFDM), the novel variable concentration shift keying (VCSK) modulation adapted to the diffusion-based transmission channel, the lowcomplex adaptive threshold detector (ATD) working without explicit channel knowledge, the low-complex soft-output piecewise linear detector (PLD), and the optimal a posteriori probability (APP) detector are of particular importance and treated. To improve the error-prone information transmission, block codes, convolutional codes, line codes, spreading codes and spatial codes are investigated. The analysis is carried out under various approaches of normalization and gains or losses compared to the uncoded transmission are highlighted. In addition to state-of-the-art forward error correction (FEC) codes, novel line codes adapted to the error statistics of the diffusion-based channel are proposed. Moreover, the turbo principle is introduced into the field of molecular communication, where extrinsic information is exchanged iteratively between detector and decoder. By means of an extrinsic information transfer (EXIT) chart analysis, the potential of the iterative processing is shown and the communication channel capacity is computed, which represents the theoretical performance limit for the system under investigation. In addition, the construction of an irregular convolutional code (IRCC) using the EXIT chart is presented and its performance capability is demonstrated. For the evaluation of all considered transmission algorithms the bit error rate (BER) performance is chosen. The BER is determined by means of Monte Carlo simulations and for some algorithms by theoretical derivation

C-Band Airport Surface Communications System Standards Development. Phase II Final Report. Volume 1: Concepts of Use, Initial System Requirements, Architecture, and AeroMACS Design Considerations

This report is provided as part of ITT s NASA Glenn Research Center Aerospace Communication Systems Technical Support (ACSTS) contract NNC05CA85C, Task 7: New ATM Requirements-Future Communications, C-Band and L-Band Communications Standard Development and was based on direction provided by FAA project-level agreements for New ATM Requirements-Future Communications. Task 7 included two subtasks. Subtask 7-1 addressed C-band (5091- to 5150-MHz) airport surface data communications standards development, systems engineering, test bed and prototype development, and tests and demonstrations to establish operational capability for the Aeronautical Mobile Airport Communications System (AeroMACS). Subtask 7-2 focused on systems engineering and development support of the L-band digital aeronautical communications system (L-DACS). Subtask 7-1 consisted of two phases. Phase I included development of AeroMACS concepts of use, requirements, architecture, and initial high-level safety risk assessment. Phase II builds on Phase I results and is presented in two volumes. Volume I (this document) is devoted to concepts of use, system requirements, and architecture, including AeroMACS design considerations. Volume II describes an AeroMACS prototype evaluation and presents final AeroMACS recommendations. This report also describes airport categorization and channelization methodologies. The purposes of the airport categorization task were (1) to facilitate initial AeroMACS architecture designs and enable budgetary projections by creating a set of airport categories based on common airport characteristics and design objectives, and (2) to offer high-level guidance to potential AeroMACS technology and policy development sponsors and service providers. A channelization plan methodology was developed because a common global methodology is needed to assure seamless interoperability among diverse AeroMACS services potentially supplied by multiple service providers

C-Band Airport Surface Communications System Standards Development, Phase I

This document is being provided as part of ITT's NASA Glenn Research Center Aerospace Communication Systems Technical Support (ACSTS) contract NNC05CA85C, Task 7: "New ATM Requirements--Future Communications, C-Band and L-Band Communications Standard Development." The proposed future C-band (5091- to 5150-MHz) airport surface communication system, referred to as the Aeronautical Mobile Airport Communications System (AeroMACS), is anticipated to increase overall air-to-ground data communications systems capacity by using a new spectrum (i.e., not very high frequency (VHF)). Although some critical services could be supported, AeroMACS will also target noncritical services, such as weather advisory and aeronautical information services as part of an airborne System Wide Information Management (SWIM) program. AeroMACS is to be designed and implemented in a manner that will not disrupt other services operating in the C-band. This report defines the AeroMACS concepts of use, high-level system requirements, and architecture; the performance of supporting system analyses; the development of AeroMACS test and demonstration plans; and the establishment of an operational AeroMACS capability in support of C-band aeronautical data communications standards to be advanced in both international (International Civil Aviation Organization, ICAO) and national (RTCA) forums. This includes the development of system parameter profile recommendations for AeroMACS based on existing Institute of Electrical and Electronics Engineering (IEEE) 802.16e- 2009 standard

Essays on the Role of Emerging Economies in International Climate Policy

Emerging economies like China and India have contributed a large share in the recent growth in global CO2 emissions, yet these countries are at a different level of economic development than industrialized countries. This dissertation asks the question of how emerging economies can contribute to international climate policies by analyzing existing and proposed policy measures. For the long run, an international regime is necessary to avoid dangerous climate change. After reviewing the literature on how different regimes would affect China and India, the impacts of one particular regime are analyzed numerically in a computable general equilibrium (CGE) model with respect to their consequences on China and India. For India, effects of the proposed policy on different household types are discussed. Furthermore, the impact of uncertainty in key abatement technologies is taken into account. For the medium run, unilateral climate policy might prevail and border carbon adjustments are proposed in order to avoid loss of competitiveness and carbon leakage. Incentives for setting certain carbon tariff rates are studied and the uncertainty in measuring emissions embodied in trade is shown, taking China as an example. Finally, a current policy measure is discussed. Taking a closer look at China, the determinants for technology transfer in the Clean Development Mechanism are analyzed.Schwellenländer wir China und Indien haben zuletzt einen Großteil des globalen Wachstums der CO2-Emission beigetragen - diese Länder sind jedoch auf einem anderen ökonomischen Entwicklungsstand als Industrieländer Diese Dissertation setzt sich mit der Frage auseinander, wie Schwellenländer zu internationaler Klimapolitik beitragen können und analysiert existierende und vorgeschlagene Politikmaßnahmen. In der langen Frist ist ein internationales Klimaregime unabdingbar, um gefährlichen Klimawandel zu vermeiden. Eine Literaturübersicht gibt zunächst Aufschluss darüber, wie verschiedene solcher Regime China und Indien beeinflussen würden, bevor die Auswirkungen eines Regimes auf China und Indien genauer in einem berechenbaren allgemeinen Gleichgewichtsmodell betrachtet werden. Für Indien werden dabei die Effekte auf verschiedene Haushaltstypen diskutiert. Zudem werden die Auswirkungen von Unsicherheiten in Schlüsseltechnologien zur CO2-Vermeidung untersucht. Mittelfristig ist jedoch keine globale Klimapolitik zu erwarten. Sich möglicherweise daraus ergebene Wettbewerbsnachteile oder Verlagerung von Emissionen konnten "Klimazölle" entgegenwirken. Die Anreize, bestimmte Zollsätze zu verwenden, werden untersucht und die Unsicherheiten der Messung von impliziten grenzüberschreitenden CO2-Flüssen am Beispiel Chinas diskutiert. Abschließend wird eine existierende Politikmaßnahme untersucht. Dabei werden die Determinanten für Technologietransfer in Projekten des Clean Development Mechanism in China bestimmt