1.
Vallejo, Luis; Mora, Jose; Ortega, Beatriz; Jin, Wei; Romero, Jaime; Tang, Jianming
Full-Duplex Transmissions in Heterogeneous Fiber-FSO-Wireless Converged Access Networks at Ka-Band Proceedings Article
In: 2025 Joint European Conference on Networks and Communications & 6G Summit (EuCNC/6G Summit), pp. 840–845, 2025, ISSN: 2575-4912, (ISSN: 2575-4912).
Abstract | Links | BibTeX | Tags: 5G mobile communication, B5G, bidirectional heterogeneous networks, converged networks, free-running lasers, Full-duplex system, fullduplex, Heterogeneous networks, Millimeter wave communication, mmWave, Phase shift keying, Radio links, Resource management, RF envelope detection, Throughput, Uplink, Wireless communication
@inproceedings{vallejo_full-duplex_2025,
title = {Full-Duplex Transmissions in Heterogeneous Fiber-FSO-Wireless Converged Access Networks at Ka-Band},
author = {Luis Vallejo and Jose Mora and Beatriz Ortega and Wei Jin and Jaime Romero and Jianming Tang},
url = {https://ieeexplore.ieee.org/document/11037218},
doi = {10.1109/EuCNC/6GSummit63408.2025.11037218},
issn = {2575-4912},
year = {2025},
date = {2025-06-01},
urldate = {2025-10-08},
booktitle = {2025 Joint European Conference on Networks and Communications & 6G Summit (EuCNC/6G Summit)},
pages = {840–845},
abstract = {To overcome the challenges associated with increased demands for mobile capacity and network densification in the 5 G and beyond era, this paper experimentally demonstrates full-duplex heterogeneous fiber-FSO-wireless converged links between the central office-baseband unit (CO-BBU) and the remote radio head (RRH). The centralization of active optical sources for the downlink (DL) and uplink (UL) enables dynamic resource sharing and allocation, optimizing wavelength utilization and improving overall network efficiency. The DL uses a directly modulated laser (DML) with free-running laser-assisted mmWave signal generation and envelope detection for the downstream, transmitting a 100 textbackslashtextMHz 16-textbackslashtextQAM signal at 39 GHz. The UL reuses the DL wavelength for upstream transmission, employing intensity modulation and direct detection (IM-DD) of a 100 MHz QPSK signal at 36.5 GHz. The bidirectional heterogeneous network comprises a 10 km SSMF, a 1.8 m FSO link, and a 3 m wireless radio link, providing flexibility for future networks. The results show successful transmissions of 16-QAM and QPSK signals up to 200 textbackslashtextMbit / textbackslashmathrms and 400 textbackslashtextMbit / textbackslashmathrms for DL and UL, respectively, under the full-duplex transmissions. Additionally, using 5G NR OFDM signals, a maximum bit rate of 2.15 textbackslashtextGbit / textbackslashmathrms and 1.07 Gbit/s is achieved for the DL and UL, respectively, demonstrating the cost-effectiveness of the proposed solution.},
note = {ISSN: 2575-4912},
keywords = {5G mobile communication, B5G, bidirectional heterogeneous networks, converged networks, free-running lasers, Full-duplex system, fullduplex, Heterogeneous networks, Millimeter wave communication, mmWave, Phase shift keying, Radio links, Resource management, RF envelope detection, Throughput, Uplink, Wireless communication},
pubstate = {published},
tppubtype = {inproceedings}
}
To overcome the challenges associated with increased demands for mobile capacity and network densification in the 5 G and beyond era, this paper experimentally demonstrates full-duplex heterogeneous fiber-FSO-wireless converged links between the central office-baseband unit (CO-BBU) and the remote radio head (RRH). The centralization of active optical sources for the downlink (DL) and uplink (UL) enables dynamic resource sharing and allocation, optimizing wavelength utilization and improving overall network efficiency. The DL uses a directly modulated laser (DML) with free-running laser-assisted mmWave signal generation and envelope detection for the downstream, transmitting a 100 textbackslashtextMHz 16-textbackslashtextQAM signal at 39 GHz. The UL reuses the DL wavelength for upstream transmission, employing intensity modulation and direct detection (IM-DD) of a 100 MHz QPSK signal at 36.5 GHz. The bidirectional heterogeneous network comprises a 10 km SSMF, a 1.8 m FSO link, and a 3 m wireless radio link, providing flexibility for future networks. The results show successful transmissions of 16-QAM and QPSK signals up to 200 textbackslashtextMbit / textbackslashmathrms and 400 textbackslashtextMbit / textbackslashmathrms for DL and UL, respectively, under the full-duplex transmissions. Additionally, using 5G NR OFDM signals, a maximum bit rate of 2.15 textbackslashtextGbit / textbackslashmathrms and 1.07 Gbit/s is achieved for the DL and UL, respectively, demonstrating the cost-effectiveness of the proposed solution.
2.
Mohammadi, Mohammadali; Mobini, Zahra; Ngo, Hien Quoc; Matthaiou, Michail
Next-Generation Multiple Access With Cell-Free Massive MIMO Journal Article
In: Proceedings of the IEEE, vol. 112, no. 9, pp. 1372–1420, 2024, ISSN: 1558-2256.
Abstract | Links | BibTeX | Tags: 5G mobile communication, 6G mobile communication, Cell-free massive multiple-input multiple-output (CF-mMIMO), Channel estimation, Energy Efficiency, energy efficiency (EE), Massive MIMO, Millimeter wave communication, Next generation networking, Signal to noise ratio, sixth-generation (6G) wireless, Spectral efficiency, spectral efficiency (SE), Surveys, Telecommunication traffic, Wireless networks
@article{mohammadi_next-generation_2024,
title = {Next-Generation Multiple Access With Cell-Free Massive MIMO},
author = {Mohammadali Mohammadi and Zahra Mobini and Hien Quoc Ngo and Michail Matthaiou},
url = {https://ieeexplore.ieee.org/document/10684238},
doi = {10.1109/JPROC.2024.3451372},
issn = {1558-2256},
year = {2024},
date = {2024-09-01},
urldate = {2025-10-08},
journal = {Proceedings of the IEEE},
volume = {112},
number = {9},
pages = {1372–1420},
abstract = {To meet the unprecedented mobile traffic demands of future wireless networks, a paradigm shift from conventional cellular networks to distributed communication systems is imperative. Cell-free massive multiple-input multiple-output (CF-mMIMO) represents a practical and scalable embodiment of distributed/network MIMO systems. It inherits not only the key benefits of co-located massive MIMO systems but also the macro-diversity gains from distributed systems. This innovative architecture has demonstrated significant potential in enhancing network performance from various perspectives, outperforming co-located mMIMO and conventional small-cell systems. Moreover, CF-mMIMO offers flexibility in integration with emerging wireless technologies such as full-duplex (FD), nonorthogonal transmission schemes, millimeter-wave (mmWave) communications, ultrareliable low-latency communication (URLLC), unmanned aerial vehicle (UAV)-aided communication, and reconfigurable intelligent surfaces (RISs). In this article, we provide an overview of current research efforts on CF-mMIMO systems and their promising future application scenarios. We then elaborate on new requirements for CF-mMIMO networks in the context of these technological breakthroughs. We also present several current open challenges and outline future research directions aimed at fully realizing the potential of CF-mMIMO systems in meeting the evolving demands of future wireless networks.},
keywords = {5G mobile communication, 6G mobile communication, Cell-free massive multiple-input multiple-output (CF-mMIMO), Channel estimation, Energy Efficiency, energy efficiency (EE), Massive MIMO, Millimeter wave communication, Next generation networking, Signal to noise ratio, sixth-generation (6G) wireless, Spectral efficiency, spectral efficiency (SE), Surveys, Telecommunication traffic, Wireless networks},
pubstate = {published},
tppubtype = {article}
}
To meet the unprecedented mobile traffic demands of future wireless networks, a paradigm shift from conventional cellular networks to distributed communication systems is imperative. Cell-free massive multiple-input multiple-output (CF-mMIMO) represents a practical and scalable embodiment of distributed/network MIMO systems. It inherits not only the key benefits of co-located massive MIMO systems but also the macro-diversity gains from distributed systems. This innovative architecture has demonstrated significant potential in enhancing network performance from various perspectives, outperforming co-located mMIMO and conventional small-cell systems. Moreover, CF-mMIMO offers flexibility in integration with emerging wireless technologies such as full-duplex (FD), nonorthogonal transmission schemes, millimeter-wave (mmWave) communications, ultrareliable low-latency communication (URLLC), unmanned aerial vehicle (UAV)-aided communication, and reconfigurable intelligent surfaces (RISs). In this article, we provide an overview of current research efforts on CF-mMIMO systems and their promising future application scenarios. We then elaborate on new requirements for CF-mMIMO networks in the context of these technological breakthroughs. We also present several current open challenges and outline future research directions aimed at fully realizing the potential of CF-mMIMO systems in meeting the evolving demands of future wireless networks.