A5082188446- Optical Network Technologies
- Advanced MIMO Systems Optimization
- Advanced Photonic Communication Systems
- Advanced Wireless Communication Technologies
- Cooperative Communication and Network Coding
- Energy Harvesting in Wireless Networks
- Indoor and Outdoor Localization Technologies
- Wireless Communication Security Techniques
- Advanced Wireless Communication Techniques
- Semiconductor Lasers and Optical Devices
- Satellite Communication Systems
- Photonic and Optical Devices
- Advanced Antenna and Metasurface Technologies
- Underwater Vehicles and Communication Systems
- IoT Networks and Protocols
- Optical Wireless Communication Technologies
- Distributed Sensor Networks and Detection Algorithms
- IoT and Edge/Fog Computing
- Microwave Engineering and Waveguides
- Advanced Optical Network Technologies
- 3D IC and TSV technologies
- Robotics and Sensor-Based Localization
- Metamaterials and Metasurfaces Applications
- PAPR reduction in OFDM
- Image Retrieval and Classification Techniques
National and Kapodistrian University of Athens
2024
Aalborg University
2022-2024
Universidade Federal de Santa Maria
2024
Universidade de São Paulo
2020-2021
Universidade Estadual de Londrina
1999-2019
LSP Technologies (United States)
2019
3S Photonics (France)
2009-2015
Institut des Sciences Moléculaires
2011
Alcatel Lucent (Germany)
2003-2004
The widespread adoption of Reconfigurable Intelligent Surfaces (RISs) in future practical wireless systems is critically dependent on the integration RIS into higher-layer protocols beyond physical (PHY) one, an issue that has received minimal attention research literature. In light this, we consider a classical random access (RA) problem, where uncoordinated users' equipment (UEs) transmit sporadically to point (AP). Differently from previous works, ponder how can be integrated design new...
In this paper, the zero-forcing and regularized schemes operating in crowded extra-large MIMO (XL-MIMO) scenarios with a fixed number of subarrays have been emulated using randomized Kaczmarz algorithm (rKA). For that, non-stationary properties deployed through concept visibility regions when considering two different power normalization methods channels. We address randomness design rKA based on exploitation spatial properties. Numerical results show general, proposed rKA-based combiner...
The research on Reconfigurable Intelligent Surfaces (RISs) has dominantly been focused physical-layer aspects and analyses of the achievable adaptation wireless propagation environment. Compared to that, questions related system-level integration RISs have received less attention. We address this gap by analyzing control signaling operations needed integrate RIS as a new infrastructure element. As main contribution paper, we build systematic procedure for evaluating impact communication...
Reconfigurable intelligent surfaces (RISs) are arrays of passive elements that can control the reflection incident electromagnetic waves. While RISs particularly useful to avoid blockages, protocol aspects for their implementation have been largely overlooked. In this paper, we devise a random access RIS-assisted wireless communication setting. Rather than tailoring RIS reflections meet positions users' equipment (UEs), our relies on finite set configurations designed cover area interest....
We report the performance of a chirped laser in IMDD-based transmissions and we show that interplay between chirp fiber dispersion can be very attractive for long distance PONs if adaptive OFDM modulation is used.
Internet of Things (IoT) connectivity has a prominent presence in the 5G wireless communication systems. As these systems are being deployed, there is surge research efforts and visions towards 6G In order to position evolution IoT within systems, this paper first takes critical view on way supported 5G. Following that, discussed through multiple dimensions: time, space, intelligence, value. We also conjecture that focus will broaden from devices their connections emergence complex...
In a cell-free massive multiple-input multiple-output (CF-mMIMO) network, multiple access points (APs) actively cooperate to serve users' equipment (UEs). We consider how the random (RA) problem can be addressed by such network under occurrence of pilot collisions. To find solution, we embrace user-centric perspective, which basically dictates that only preferred set APs needs UE. Due success strongest-user collision resolution (SUCRe) protocol for cellular (Ce) mMIMO, extend it considering...
Abstract To provide the vast exploitation of large number antennas on massive multiple‐input–multiple‐output (M‐MIMO), it is crucial to know as accurately possible channel state information in base station. This knowledge canonically acquired through estimation procedures conducted after a pilot signaling phase, which adopts widely accepted time‐division duplex scheme. However, quality very impacted either by contamination or spatial correlation channels. There are several models that strive...
To exploit the benefits of massive multiple-input multiple-output (M-MIMO) technology in scenarios where base stations (BSs) need to be cheap and equipped with simple hardware, computational complexity classical signal processing schemes for spatial multiplexing users shall reduced. This calls suboptimal designs that perform well combining/precoding steps simultaneously achieve low complexities. An approach based on iterative Kaczmarz algorithm (KA) has been recently investigated, assuring...
This paper presents the design and performance of a single-ended transimpedance amplifier (TIA) for gigabit passive optical networks implementing orthogonal frequency division multiplexing modulation format. The circuit is realized using an industrial GaAs integrated technology. Low power consumption small chip area are main challenges in TIA design. On-wafer characterization terms <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">S</i>...
We report on the design and characterization of a high-power high dynamic range directly modulated analog fiber optic link in S (2-4 GHz) band. The is amplifier free, uses passive impedance matching networks associated to power laser diode photodiode. Thanks components efficiencies, together with benefit reactive matchings, we achieved gain (≥ 0 dB) over 500 MHz bandwidths. Moreover, use linearity allowed us achieve simultaneously an output -1dB compression point higher than 20 dBm, third...
Adaptively modulated optical orthogonal frequency division multiplexing (AMOOFDM) modulation is experimentally evaluated using different photodiodes. A comparison made between positive-intrinsic-negative (pin) and avalanche photodiode (APD) receivers in next generation passive network (NG-PON) downlink architecture. Direct transmission as well direct detection reception allows reducing the cost of system. The results are obtained respecting requirements a class B+ budget. An additional...
This paper investigates the role and impact of control operations for dynamic mobile edge computing (MEC) empowered by Reconfigurable Intelligent Surfaces (RISs), in which multiple devices offload their computation tasks to an access point (AP) equipped with server (ES), help RIS. While usually ignored, aspect related signaling, channel estimation (CE), resource allocation (RA) procedures plays a fundamental user-perceived delay energy consumption. In general, higher resources involved...
Despite the extensive use of a centralized approach to design receivers for massive multiple-input multiple-output (M-MIMO) base stations, their actual implementation is major challenge due several bottlenecks imposed by large number antennas. One way deal with this problem fully decentralizing classical zero-forcing (ZF) receiver across multiple processing nodes based on gradient descent (GD) method. In paper, we first explicitly relate decentralized distributed version Kaczmarz algorithm...
The wavelength emitted from a 2.5 Gbit/s integrated electroabsorption modulator/DFB laser module is tuned over 3.2 nm via the chip temperature control, while sensitivity penalties caused by chromatic dispersion of 770 km standard fibre remain <1 dB. This significantly relaxes manufacturers' constraints on specifications in scope multichannel systems.
We present the results of implementation two VCSEL-based optoelectronic oscillators (VBO) using one on-chip 850-nm vertical-cavity surface-emitting laser (VCSEL). The reported VBOs are implemented at 10 and 12 GHz a direct-modulated VCSEL. direct modulation bandwidth is 13.3 GHz. performance described through phase noise time-domain stability.
To obviate the control of reflective intelligent surfaces (RISs) and related overhead, recent works envisioned autonomous self-configuring RISs that do not need explicit use channels. Instead, these devices, named hybrid (HRISs), are equipped with receiving radio-frequency (RF) chains can perform sensing operations to act independently in parallel other network entities. A natural problem then emerges: as HRIS operates concurrently communication protocols, how should its operation modes be...
This paper introduces EcoPull, a sustainable Internet of Things (IoT) framework empowered by tiny machine learning (TinyML) models for fetching images from wireless visual sensor networks. Two types learnable TinyML are installed in the IoT devices: i) behavior model and ii) an image compressor model. The first filters out irrelevant current task, reducing unnecessary transmission resource competition among devices. second allows devices to communicate with receiver via latent...