Amalia Miliou

Aristotle University of Thessaloniki

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Nikos Pleros

Aristotle University of Thessaloniki

107

Christos Vagionas

Aristotle University of Thessaloniki

George Kalfas

Aristotle University of Thessaloniki

George T. Kanellos

University of Bristol

Eugenio Ruggeri

Aristotle University of Thessaloniki

T. Alexoudi

Aristotle University of Thessaloniki

Konstantinos Vyrsokinos

Aristotle University of Thessaloniki

Stavros G. Stavrinides

International Hellenic University

Charoula Mitsolidou

LioniX (Netherlands)

Apostolos Tsakyridis

Aristotle University of Thessaloniki

Cooperative Institutions

National and Kapodistrian University of Athens

Aristotle University of Thessaloniki

Centre Tecnologic de Telecomunicacions de Catalunya

University of South Wales

Qatar University

Iquadrat (Spain)

Instituto de Telecomunicações

Syracuse University

National Technical University of Athens

III V Lab

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Linearity Measurements on a 5G mmWave Fiber Wireless IFoF Fronthaul Link With Analog RF Beamforming and 120° Degrees Steering

IEEE Communications Letters (2020)

Christos Vagionas Eugenio Ruggeri Apostolos Tsakyridis George Kalfas Yigal Leiba

Towards the 5G millimeter Wave (mmWave) era, analog transport offers a spectrally efficient scheme for converged Fiber Wireless (FiWi) networks. Signal integrity is traditionally considered as a limiting factor due to various non-linearities attributed to the microwave photonic link, expected to be further exacerbated by the RF-chain of beamforming Phased Array Antennas (PAAs). The letter proposes the end-to-end evaluation of FiWi analog links as unified communication channels rather than separately for the radio or optical part, presenting a link with a 32-element 60 GHz PAA, 1 m V-band distance, 10 km fiber and 10 dB dynamic range. The measurements reveal a third order Intercept Point (IIP3) of 4.8 dBm, compared to 22.8 dBm exclusively for the optics, pinpointing the V-band radio as the main source of degradation rather than the microwave photonic link. Single user uplink is also benchmarked using 300 Mbd QPSK, 250 16-QAM and 100 Mbd 32-QAM, achieving data-rate up to 1 Gb/s and beamsteering of 120° degrees.

Optical link

True time delay

10.1109/lcomm.2020.3019733

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Citations (16)

Multi-RAT Fiber-Wireless Technologies towards 6G Networks

Christos Vagionas Ronis Maximidis Κωνσταντίνα Καντά Panagiotis Toumasis Giannis Giannoulis

At the dawning of the beyond 5G era, broadband last mile connectivity is stimulating rapid developments in optical and wireless technologies that will efficiently handle the traffic generated by mobile users and demanding network applications. To this end, multiple Radio Access (multi-RAT) technologies operating at various millimeter wave (mmWave) frequency bands, e.g., V-/E-/D-band are being actively pursued, in parallel with the investigation of efficient fiber wireless fronthaul schemes, e.g. Analog Radio over Fiber (aRoF) or Intermediate Frequency over Fiber (IFoF), to deliver low-complexity, broadband, last-mile connectivity. However, integration of such novel technologies in an actual mobile network infrastructure remains a challenge, as it needs to support compatibility with the network operators' equipment. The current talk aims to present a holistic Fiber Wireless (FiWi) connectivity, demonstrating the co-existence of Analog and Digital RoF traffic along with flexible, reconfigurable point-to-multipoint connectivity to multi-RAT antenna units. Experimental results on high capacity FiWi fronthaul links operating in the V- (60 GHz) and D- (145 GHz) will be presented. Moreover, end-to-end, integrated real-time traffic and network operation will also be discussed and experimentally presented, indicating a possible technology roadmap towards multi-RAT 6G networks.

Access network

Extremely high frequency

Mobile broadband

10.1109/icton59386.2023.10207366

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Citations (2)

Testing Stability and Robustness in Three Cryptographic Chaotic Systems

Antonios N. Anagnostopoulos Kon Konstantinidis Nos Stavros G. Stavrinides Amalia Miliou

Robustness

Chaotic systems

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Optical RAM and Flip-Flops Using Bit-Input Wavelength Diversity and SOA-XGM Switches

Journal of Lightwave Technology (2012)

Christos Vagionas D. Fitsios George T. Kanellos Nikos Pleros Amalia Miliou

In this paper, we demonstrate a novel RAM cell based only on three traveling waveguide semiconductor optical amplifier-cross gain modulation (SOA-XGM) switches. The RAM cell features wavelength diversity in the incoming bit signals and provides Read/Write operation capability with true random access exclusively in the optical domain. Two of the SOA-XGM switches are coupled together through an 70/30 coupler to form an asynchronous flip-flop, which serves as the memory unit. Random access to the memory unit is granted by a third SOA-ON/OFF switch and all three SOAs together form the proposed RAM cell. Proof-of-principle operation is experimentally demonstrated at 8 Mb/s using commercial fiber-pigtailed components. The distinctive simplicity of the proposed RAM cell architecture suggests reduced footprint. The proposed flip-flop layout holds all the credentials for reaching multi-Gb/s operational speeds, if photonic integration technologies are employed to obtain wavelength-scale waveguides and ultrashort coupling lengths. This is numerically confirmed for 10 Gb/s using a simulation model based on the transfer matrix method and a wideband steady-state material gain coefficient.

10.1109/jlt.2012.2210696

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Citations (41)

Channel Equalization for converged OFDM-Based 5G mm-wave A-RoF System at 60 GHz

2022 IEEE 12th Annual Computing and Communication Workshop and Conference (CCWC) (2021)

Umar Farooq Amalia Miliou

In this article, we are presenting, using simulations, a converged analogue radio-over-fiber (A-RoF) 5G mm-wave system at 60GHz and we are compensating the dispersion in the optical link with a simple least mean square (LMS) equalizing algorithm applied in Matlab inversing the transmission channel impairments. Quadrature Amplitude Modulation (QAM) 4 and 16 are used in the Orthogonal Frequency Division Multiplexing (OFDM) subcarriers and greatest communication distance of 25 km and 15 km are achieved respectively after equalization.

QAM

Modulation (music)

Adaptive equalizer

10.1109/ccwc51732.2021.9375831

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Citations (4)

End-to-End Real-Time Service Provisioning Over a SDN-Controllable Analog mmWave Fiber -Wireless 5G X-Haul Network

Journal of Lightwave Technology (2023)

Christos Vagionas Ronis Maximidis Ioannis Stratakos A. Margaris Agapi Mesοdiakaki

The current work presents the first experimental demonstration of real-time Ethernet (ETH) trial services and 4K-Ultra High Definition (UHD) video application transmission over a 2λ Wavelength Division Multiplexing (WDM) analog Fiber-Wireless (FiWi) mmWave X-haul network, supporting dynamic flexible capacity allocation through an integrated silicon photonic Si ₃ N ₄ Reconfigurable Optical Add Drop Multiplexer (ROADM) and 60 GHz wireless transmission across a 7 m V-band link distance, while controlled by a Software Defined Network (SDN) controller based on Open Daylight. Analog X-haul transport of the radio signals is based on an Intermediate Frequency over Fiber (IFoF) scheme centered at 1.5 GHz using an Orthogonal Frequency Division Multiplexing (OFDM) radio-waveform with a bandwidth of 204 MHz, generated by a Field Programmable Gated Array (FPGA)-based RF System-on-Chip (SoC) processor that converts on-the-fly the real-time ETH downlink traffic to analog radio and vice-versa for the uplink. Dynamic allocation of the X-haul traffic capacity is handled through the use of the 802.1Q Virtual Local Area Network (VLAN) tag-mechanism, which controls the forwarding operation to the proper DAC and InP EML for optical modulation using Intensity Modulation/Direct Detection (IM/DD) schemes, while the wavelength routing operation is handled by the low-loss four-port Si ₃ N ₄ ROADM featuring only 2.5 dB fiber-to-fiber losses based on a cascaded MZI-interleaver design on the TriPleX platform, routing the real-time traffic to a second mmWave antenna site. Detailed measurements and traffic statistics indicate end-to-end latency of less than 260 μs and a packet loss less than 0.0054% across a dynamic range of at least 6.5 dB in the optical domain, while the high user bandwidth and signal quality are validated by an uninterrupted 4K-UHD video transmission across the FiWi X-haul mmWave transport network. The current work aims to shape a complete technology roadmap for Point-to-Multipoint FiWi transport network architectures with high spectral efficiency X-haul transport for dense areas and 5G/6G hotspots of future mmWave Centralized Radio Access Networks (C-RANs).

Optical networking

10.1109/jlt.2023.3234365

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Citations (26)

Flexible 360o 5G mmWave small cell coverage through WDM 4x1 Gb/s Fiber Wireless fronthaul and a Si3N4 OADM-assisted massive MIMO Phased Array Antenna

Optical Fiber Communication Conference (OFC) 2022 (2020)

Eugenio Ruggeri Apostolos Tsakyridis Christos Vagionas George Kalfas Ruud M. Oldenbeuving

Four Wavelength Division Multiplexed 1Gb/s QAM16 streams are transmitted through 10km fiber, an Optical Add/Drop Multiplexer and a V-band beamsteering antenna with 90° steering, demonstrating the first 5G Fiber-Wireless A-RoF architecture with 360o coverage.

Optical add-drop multiplexer

10.1364/ofc.2020.t4a.5

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Citations (3)

A 10Gb/S Optical Random-Access Memory Using a Saturated SOA-MZI Fast Access Gate and a Monolithic InP Flip-Flop

Conference on Lasers and Electro-Optics (2019)

Apostolos Tsakyridis Christos Vagionas Th. Alexoudi Amalia Miliou Nikos Pleros

We experimentally demonstrate an all-optical static Random-Access Memory (RAM)cell using a monolithic integrated InP Flip-Flop and a fast strongly-saturated push-pull SOA-MZI Access-Gate, reporting 10Gb/s error-free Write/Read operation and the fastest RAM cell to date. © 2019 The Author(s)

Flip-flop

Random access

10.23919/cleo.2019.8750503

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Advanced DFE and MLD Techniques for Enhanced 5G mm-Wave A-RoF Performance at 60 GHz

Umar Farooq Amalia Miliou

This article presents the Decision Feedback Equalizer (DFE) and the Maximum Likelihood detection (MLD) algorithms designed in MATLAB to equalize the received signal in a dispersive optical link up to 120 Km. The algorithms are tested using a converged 5G mm-wave analog radio-over-fiber (A-RoF) system at 60 GHz. The algorithm’s performance is measured regarding error vector magnitude (EVM) values before and after equalization, for different optical fiber lengths and modulation formats (QPSK, 16-QAM, 64-QAM, and 128-QAM) and shows a clear performance improvement of the output signal. Moreover, the performance of the proposed algorithms is compared to three commonly used algorithms: the simple least mean square (LMS) algorithm, the constant modulus algorithm (CMA), and the adaptive median filtering (AMF) demonstrating superior results in both QPSK and 16-QAM and extending the transmission distance up to 120 km. DFE has a significant advantage over LMS and AMF in reducing the inter-symbol interference (ISI) in a dispersive channel by using previous decision feedback, resulting in quicker convergence and more precise equalization. MLD on the other hand is highly effective in improving detection accuracy by taking into account the probability of various symbol sequences achieving lower error rates and enhancing performance in advanced modulation schemes. Furthermore, DFE and MLD are particularly suitable for higher-order modulation formats like 64-QAM and 128-QAM, where accurate equalization and error detection are of utmost importance. The enhanced functionalities of DFE and MLD in managing greater modulation orders and expanding transmission range highlight their efficacy in improving the performance and dependability of our system.

10.20944/preprints202501.0583.v1

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All-optical digital physical-layer network coding for DPSK mm-wave Radio-over-Fiber networks

Charoula Mitsolidou Nikos Pleros Amalia Miliou

We demonstrate the first all-optical digital physical-layer network coding (AOPNC) for Differential Phase Shift Keyed (DPSK) Sub-Carrier Modulated (SCM) signals in mm-wave Radio-over-Fiber (RoF) networks. AOPNC is performed at the Central Office (CO) by employing a Delay Interferometer (DI) for phase-to-amplitude conversion, two Semiconductor Optical Amplifier-Mach Zehnder Interferometers (SOA-MZIs) performing the XOR and XNOR operation between the OOK converted signals and a third SOA-MZI for the phase regeneration of the encoded phase-formatted XOR signal. Encoding and decoding are evaluated via simulations for 2.5 Gb/s NRZ-DPSK data modulated on 60 GHz SC for both synchronous and asynchronous operation.

XNOR gate

10.1109/icton.2017.8025159

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Citations (2)