Design and implementation of digital signal processing algorithms and optical circuits in 5G optical networks

Abstract

In the context of this doctoral thesis, the design and implementation of digital signal processing algorithms and optical circuits in 5G optical networks is being investigated. More specifically, the development of an end-to-end transceiver signal processing toolbox, that is tailor made for the generation, demodulation, and treatment of multicarrier signals, that are appropriate for converged analog fiber-wireless transmission schemes is presented. The validation of the functionality of this toolbox, as well as the performance evaluation of CP-OFDM signals propagated over different optical and optical-wireless layouts is showcased within the current document, through the presentation of small-scale laboratory setups and field-trials. In all cases, the bandwidth efficient Analog IFoF transmission scheme, along with mmWave radio equipment have been employed. The DSP-assisted deployed testbeds emulate transport alternatives, aiming to provide efficient solutions towards efficient future mobile X-Haul infrastructures by focusing on the integrability of the investigated transport link into actual Mobile Network Operators’ fiber deployments and mobile equipment. Chapter 1 is an introductory chapter that lays the groundwork for understanding the historical trajectory and transformative milestones that have shaped the mobile communication ecosystem. Moving forward, the pivotal role of optical access network Interfaces in the era of 5G and beyond is illustrated. The exploration deepens with a dedicated focus on Future mobile networks' applications and use cases providing insights into the anticipated applications and performance metrics that will define the landscape of mobile networks in the foreseeable future and pave the path towards future RAN evolution strategies. Chapter 2 investigates analog fiber-wireless links as a crucial element for efficient RAN extensions in 5G networks. This chapter covers various aspects, including the transition to C-RAN architectures, optical transport for MFH, and DSP-assisted analog Fronthaul. Analog RoF-based mobile Fronthaul, mmWave wireless technologies, and proof-of-concept experimental evaluations are also explored. Moving forward, Chapter 3 delves into modulation and signal processing techniques, elucidating the role of these techniques in supporting analog fiber and fiber-wireless transport transmission. It encompasses an in-depth examination of digital modulation schemes, OFDM modulation, multi-carrier candidates for 5G, and the integration of DSP algorithms for processing CP-OFDM waveforms. Chapter 4 shifts the focus to analog fiber-wireless downlink transmission of IFoF/mmWave over in-field deployed legacy PON infrastructure, presenting a detailed analysis of converged PON/mmWave topology through experimental evaluation. The dissertation culminates in Chapter 5, where a live demonstration of an SDN-reconfigurable, FPGA-based TxRx for Analog-IFoF/mmWave RAN is showcased. This chapter provides insights into the envisioned Fronthaul architecture, RFSoC-based A-IFoF transceivers, SDN-powered Management & Control Plane, and the experimental evaluation of the real-time analog Fronthaul topology. In the final chapter, Chapter 6, the dissertation concludes by summarizing key findings and insights gained throughout the exploration of analog fiber and fiber-wireless transport in the realm of 5G networks, while also discussing future research extensions related to the presented work.