Advanced digital signal processing for next-generation flexible optical networks

To keep pace with the rapid expansion in data-exchange traffic around the world, optical networks are anticipated to provide flexibility to maximize utilization of the deployed optical fiber resources. On the other hand, digital signal processing (DSP) has been employed in coherent optical systems to enable 100G and beyond optical fiber networks. The goal of the thesis is to develop advanced DSP techniques for the flexible optical networks. With the reconfigured modulation formats in the systems, modulation classification (MC) is essential in the DSP to facilitate the sequential compensation modules which are modulation format-dependent. Based on the cumulative distribution function (CDF) of received signal's amplitude, an MC algorithm for M-ary quadrature amplitude modulation (M-QAM) formats with M = 4, 8, 16, 32, and 64 is proposed. Results show that the proposed algorithm achieves accurate classification at optical signal-to-noise ratio (OSNR) of interest and is robust to frequency offset and laser phase noise. Relying on the CDF of received signal's amplitude, a non-data-aided (NDA) OSNR estimation algorithm is developed for coherent optical systems employing multilevel constellations. It outperforms the state-of-the-art NDA algorithm in terms of performance and complexity. Furthermore, a joint OSNR estimation and MC algorithm enabled by support vector machine is designed. Compared to deep neural network-based joint estimation approach, the proposed algorithm achieves better performance with comparable complexity. In addition, a low-complexity two-stage carrier phase estimation algorithm is proposed for coherent optical systems with 16-QAM format. The proposed algorithm exploits the second power operation instead of the conventional fourth power to remove the modulation phase, which is enabled by constellation partition and rotation. Optical back-to-back experiments and numerical simulations are carried out to evaluate the performance of the algorithm. Results show that, compared with the conventional fourth power-based CPE algorithm, the proposed algorithm provides comparable tolerance to the carrier phase noise, with reduced complexity. Lastly, a novel transmission scheme is investigated for the open and disaggregated metro coherent optical networks, which impose the requirements for multiple user connectivities on the limited orthogonal frequency resources. Thus, it is desirable to provide connections simultaneously to various users in a non-orthogonal way. A transmission scheme based on the non-orthogonal sparse code multiple access in a digital subcarrier multiplexing is proposed. Compared to power domain-based counterpart, the proposed scheme supports more than 2 users without user pairing and clustering. The feasibility of the proposed scheme is verified through numerical simulations. Three scenarios with 2, 4, and 6 users over 1, 2, and 4 subcarriers, respectively, are considered. Performance evaluations show that in all scenarios, the proposed scheme attains bit error ratio lower than the forward error correction limits with the transmission ranges of interest in metro applications

Timing and Carrier Synchronization in Wireless Communication Systems: A Survey and Classification of Research in the Last 5 Years

Timing and carrier synchronization is a fundamental requirement for any wireless communication system to work properly. Timing synchronization is the process by which a receiver node determines the correct instants of time at which to sample the incoming signal. Carrier synchronization is the process by which a receiver adapts the frequency and phase of its local carrier oscillator with those of the received signal. In this paper, we survey the literature over the last 5 years (2010–2014) and present a comprehensive literature review and classification of the recent research progress in achieving timing and carrier synchronization in single-input single-output (SISO), multiple-input multiple-output (MIMO), cooperative relaying, and multiuser/multicell interference networks. Considering both single-carrier and multi-carrier communication systems, we survey and categorize the timing and carrier synchronization techniques proposed for the different communication systems focusing on the system model assumptions for synchronization, the synchronization challenges, and the state-of-the-art synchronization solutions and their limitations. Finally, we envision some future research directions

Proceedings of the Third International Mobile Satellite Conference (IMSC 1993)

Satellite-based mobile communications systems provide voice and data communications to users over a vast geographic area. The users may communicate via mobile or hand-held terminals, which may also provide access to terrestrial cellular communications services. While the first and second International Mobile Satellite Conferences (IMSC) mostly concentrated on technical advances, this Third IMSC also focuses on the increasing worldwide commercial activities in Mobile Satellite Services. Because of the large service areas provided by such systems, it is important to consider political and regulatory issues in addition to technical and user requirements issues. Topics covered include: the direct broadcast of audio programming from satellites; spacecraft technology; regulatory and policy considerations; advanced system concepts and analysis; propagation; and user requirements and applications

MIMO Systems

In recent years, it was realized that the MIMO communication systems seems to be inevitable in accelerated evolution of high data rates applications due to their potential to dramatically increase the spectral efficiency and simultaneously sending individual information to the corresponding users in wireless systems. This book, intends to provide highlights of the current research topics in the field of MIMO system, to offer a snapshot of the recent advances and major issues faced today by the researchers in the MIMO related areas. The book is written by specialists working in universities and research centers all over the world to cover the fundamental principles and main advanced topics on high data rates wireless communications systems over MIMO channels. Moreover, the book has the advantage of providing a collection of applications that are completely independent and self-contained; thus, the interested reader can choose any chapter and skip to another without losing continuity

Cooperative Radio Communications for Green Smart Environments

The demand for mobile connectivity is continuously increasing, and by 2020 Mobile and Wireless Communications will serve not only very dense populations of mobile phones and nomadic computers, but also the expected multiplicity of devices and sensors located in machines, vehicles, health systems and city infrastructures. Future Mobile Networks are then faced with many new scenarios and use cases, which will load the networks with different data traffic patterns, in new or shared spectrum bands, creating new specific requirements. This book addresses both the techniques to model, analyse and optimise the radio links and transmission systems in such scenarios, together with the most advanced radio access, resource management and mobile networking technologies. This text summarises the work performed by more than 500 researchers from more than 120 institutions in Europe, America and Asia, from both academia and industries, within the framework of the COST IC1004 Action on "Cooperative Radio Communications for Green and Smart Environments". The book will have appeal to graduates and researchers in the Radio Communications area, and also to engineers working in the Wireless industry. Topics discussed in this book include: • Radio waves propagation phenomena in diverse urban, indoor, vehicular and body environments• Measurements, characterization, and modelling of radio channels beyond 4G networks• Key issues in Vehicle (V2X) communication• Wireless Body Area Networks, including specific Radio Channel Models for WBANs• Energy efficiency and resource management enhancements in Radio Access Networks• Definitions and models for the virtualised and cloud RAN architectures• Advances on feasible indoor localization and tracking techniques• Recent findings and innovations in antenna systems for communications• Physical Layer Network Coding for next generation wireless systems• Methods and techniques for MIMO Over the Air (OTA) testin

Cooperative Radio Communications for Green Smart Environments

The demand for mobile connectivity is continuously increasing, and by 2020 Mobile and Wireless Communications will serve not only very dense populations of mobile phones and nomadic computers, but also the expected multiplicity of devices and sensors located in machines, vehicles, health systems and city infrastructures. Future Mobile Networks are then faced with many new scenarios and use cases, which will load the networks with different data traffic patterns, in new or shared spectrum bands, creating new specific requirements. This book addresses both the techniques to model, analyse and optimise the radio links and transmission systems in such scenarios, together with the most advanced radio access, resource management and mobile networking technologies. This text summarises the work performed by more than 500 researchers from more than 120 institutions in Europe, America and Asia, from both academia and industries, within the framework of the COST IC1004 Action on "Cooperative Radio Communications for Green and Smart Environments". The book will have appeal to graduates and researchers in the Radio Communications area, and also to engineers working in the Wireless industry. Topics discussed in this book include: • Radio waves propagation phenomena in diverse urban, indoor, vehicular and body environments• Measurements, characterization, and modelling of radio channels beyond 4G networks• Key issues in Vehicle (V2X) communication• Wireless Body Area Networks, including specific Radio Channel Models for WBANs• Energy efficiency and resource management enhancements in Radio Access Networks• Definitions and models for the virtualised and cloud RAN architectures• Advances on feasible indoor localization and tracking techniques• Recent findings and innovations in antenna systems for communications• Physical Layer Network Coding for next generation wireless systems• Methods and techniques for MIMO Over the Air (OTA) testin