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235 Results Found

  • Review
  • Open Access
30 Citations
19,010 Views
110 Pages

16 December 2024

As the demand for high-speed, low-latency communication continues to grow, free-space optical (FSO) communication has gained prominence as a promising solution for supporting the next generation of wireless networks, especially in the context of the...

  • Review
  • Open Access
60 Citations
8,492 Views
55 Pages

31 October 2022

Increased capacity, higher data rate, decreased latency, and better service quality are examples of the primary objectives or needs that must be catered to in the near future, i.e., fifth-generation (5G) and beyond. To fulfil these needs, cellular ne...

  • Article
  • Open Access
5 Citations
1,441 Views
14 Pages

Modern cellular systems rely on high-capacity and low-latency optical networks to meet ever-increasing data demands. Centralized Radio Access Network (C-RAN) architectures offer a cost-effective approach for deploying mobile infrastructures. In this...

  • Article
  • Open Access
4 Citations
2,515 Views
17 Pages

Implementation of Shared Laser–LED Sources in a Free Space Optics (FSO) Network under Environmental Impact

  • Abu Sufian Abdallah Hassan,
  • Hassan Yousif Ahmed,
  • Hilal A. Fadhil,
  • Medien Zeghid,
  • Abdellah Chehri and
  • Somia A. Abd El-Mottaleb

This paper is devoted to evaluating the combined coherent and incoherent sources (CCIS) technique for different applications in the optical domain and future optical code division multiple access (OCDMA) networks. Spectral amplitude coding (SAC) has...

  • Article
  • Open Access
2,290 Views
19 Pages

2 December 2024

Free Space Optics (FSO)-based UAV-enabled wireless power transfer (WPT) relay systems have emerged as a key technology for 6G networks, efficiently providing continuous power to Internet of Things (IoT) devices even in remote areas such as disaster r...

  • Communication
  • Open Access
14 Citations
2,857 Views
10 Pages

Hybrid Self-Protected Fiber-FSO WDM-PON System with Fiber Breakage Prevention

  • Ching-Hsuan Hsu,
  • Syu-Yang Jiang,
  • Shang-En Hsieh,
  • Chien-Hung Yeh,
  • Yu-Ting Lai,
  • Lan-Yin Chen,
  • Shien-Kuei Liaw and
  • Chi-Wai Chow

2 November 2022

In this research, we present and design a blended wavelength-division-multiplexing passive optical network (WDM-PON) architecture to deliver both baseband and free-space optical (FSO) signals by using two wavelength bands over an available bandwidth...

  • Communication
  • Open Access
8 Citations
3,155 Views
11 Pages

Integrated Fiber-FSO WDM Access System with Fiber Fault Protection

  • Chien-Hung Yeh,
  • Wen-Piao Lin,
  • Syu-Yang Jiang,
  • Shang-En Hsieh,
  • Ching-Hsuan Hsu and
  • Chi-Wai Chow

In this study, we propose a new wavelength-division-multiplexing passive optical network (WDM-PON) system to support the blended fiber-free space optics (FSO) signal access. To provide the fiber and FSO traffics simultaneously, the C- and L-band chan...

  • Article
  • Open Access
9 Citations
6,655 Views
17 Pages

Free Space Optical Communication Networking Technology Based on a Laser Relay Station

  • Changchun Ding,
  • Chengming Li,
  • Ziming Wang,
  • Zhen Gao,
  • Zijian Liu,
  • Junfeng Song and
  • Min Tao

16 February 2023

Optical communication modulation technology and networking technology are two important technologies for constructing free-space optical (FSO) communication. In this paper, pulse width modulation (PWM) is used to realize free-space optical communicat...

  • Article
  • Open Access
21 Citations
7,347 Views
17 Pages

29 January 2015

This paper proposes a theoretical study to characterize the transmission of optical code division multiple access (CDMA) systems deploying polarization shift keying (PolSK) over a free space optical (FSO) link under the impact of atmospheric turbulen...

  • Article
  • Open Access
8 Citations
3,478 Views
16 Pages

Free Space Optics (FSO) technology enabling next-generation near-Earth communication is prone to severe propagation losses due to atmospheric-turbulence-induced fading and Mie scattering (clouds). As an alternative to the real-time evaluation of the...

  • Article
  • Open Access
16 Citations
3,193 Views
16 Pages

Capacity Enhancement Analysis of an OAM-OFDM-SMM Multiplexed Free Space Communication System in Atmospheric Turbulence

  • Shivaji Sinha,
  • Chakresh Kumar,
  • Ammar Armghan,
  • Mehtab Singh,
  • Meshari Alsharari and
  • Khaled Aliqab

19 March 2023

To overcome atmospheric turbulence (AT) distortion during signal propagation through the optical link, orbital angular momentum (OAM) mode states employing multiple inputs and multiple outputs (MIMO) techniques have recently gained prominence in free...

  • Article
  • Open Access
2 Citations
1,141 Views
12 Pages

A Self-Healing WDM Access Network with Protected Fiber and FSO Link Paths Effective Against Fiber Breaks

  • Tsu-Hsin Wu,
  • Chien-Yu Liao,
  • Chien-Hung Yeh,
  • Yuan-Wen Chen,
  • Yu-Hsin Kao,
  • Sung-Yi Lin,
  • Yu-Heng Lin and
  • Shien-Kuei Liaw

In this article, an additional protected fiber and free-space optical (FSO) link path is proposed, to provide self-healing capabilities for protection against fiber faults in wavelength division multiplexed passive optical network (WDM-PON) systems....

  • Article
  • Open Access
2 Citations
4,123 Views
13 Pages

Multi-Tier Heterogeneous Beam Management for Future Indoor FSO Networks

  • Michael B. Rahaim,
  • Thomas D. C. Little and
  • Mona Hella

17 April 2021

To meet the growing demand for wireless capacity, communications in the Terahertz (THz) and optical bands are being broadly explored. Communications within these bands provide massive bandwidth potential along with highly directional beam steering ca...

  • Article
  • Open Access
31 Citations
5,665 Views
16 Pages

Performance Analysis and Enhancement of Free Space Optical Links for Developing State-of-the-Art Smart City Framework

  • Sonali Chauhan,
  • Rajan Miglani,
  • Lavish Kansal,
  • Gurjot Singh Gaba and
  • Mehedi Masud

16 December 2020

In this paper, we have investigated and reported the performance of free-space optical (FSO) links operating in adverse atmospheric conditions. Since FSO links share operational similarity with fiber communication; hence, we believe that a cost-effec...

  • Article
  • Open Access
46 Citations
6,346 Views
10 Pages

Performance Analysis of Hard-Switching Based Hybrid FSO/RF System over Turbulence Channels

  • Hira Khalid,
  • Sajid Sheikh Muhammad,
  • Hector E. Nistazakis and
  • George S. Tombras

The hybrid system of free space optic (FSO) and radio frequency (RF) has come forth as alternative good solution for increasing demand for high data rates in wireless communication networks. In this paper, wireless networks with hard-switching betwee...

  • Communication
  • Open Access
26 Citations
2,746 Views
9 Pages

15 January 2023

Hybrid free-space optics (FSO) and optical fiber have been viewed as vital transmission techniques to satisfy high bandwidth and extended transmission range requirements under adverse environment conditions in the future last-mile obstruction problem...

  • Article
  • Open Access
6 Citations
2,272 Views
20 Pages

A Hybrid Millimeter-Wave and Free-Space-Optics Communication Architecture with Adaptive Diversity Combining and HARQ Techniques

  • Yinjun Liu,
  • Xiaochuan Tan,
  • Junlian Jia,
  • Boyu Dong,
  • Changle Huang,
  • Penghao Luo,
  • Jianyang Shi,
  • Nan Chi and
  • Junwen Zhang

29 November 2023

We propose and demonstrate a hybrid communication architecture that combines millimeter-wave (MMW) in the radio frequency (RF) domain and free-space-optics (FSO) technologies using adaptive combining and hybrid automatic repeat request (HARQ) techniq...

  • Feature Paper
  • Article
  • Open Access
14 Citations
6,431 Views
14 Pages

19 February 2024

Space–air–ground integrated network (SAGIN) is considered an enabler for sixth-generation (6G) networks. By integrating terrestrial and non-terrestrial (satellite, aerial) networks, SAGIN seems to be a quite promising solution to provide...

  • Article
  • Open Access
1 Citations
1,130 Views
18 Pages

24 June 2025

Free space optics (FSO) aims to perform as one of the best optical wireless channels to design a reliable, flexible, and cost-effective communication system. In FSO systems, mode-division multiplexing (MDM) transmission is a proven technique to expan...

  • Article
  • Open Access
40 Citations
13,110 Views
45 Pages

30 October 2023

The deployment of non-terrestrial networks (NTNs) is envisioned to achieve global coverage for 6G and beyond. In addition to space nodes, aerial NTN nodes such as high-altitude platform stations (HAPSs) and rotary-wing unmanned aerial vehicles (UAVs)...

  • Article
  • Open Access
1,647 Views
17 Pages

4 August 2025

Free-space optical (FSO) communications have emerged as a promising complement to conventional radio-frequency (RF) systems due to their high bandwidth, low interference, and license-free spectrum. Visible-light FSO communication, using laser diodes...

  • Article
  • Open Access
16 Citations
4,114 Views
13 Pages

Performance Improvement for Mixed RF–FSO Communication System by Adopting Hybrid Subcarrier Intensity Modulation

  • Ting Jiang,
  • Lin Zhao,
  • Hongzhan Liu,
  • Dongmei Deng,
  • Aiping Luo,
  • Zhongchao Wei and
  • Xiangbo Yang

6 September 2019

The improvement for hybrid radio frequency–free space optical (RF–FSO) communication system in wireless optical communications has acquired growing interests in recent years, but rarely improvement is based on hybrid modulation. Therefore...

  • Article
  • Open Access
1 Citations
1,247 Views
12 Pages

24 September 2024

In this paper, we analyze the confidentiality of a hybrid radio frequency (RF)/free-space optical (FSO) system with regard to physical layer security (PLS). In this system, signals are transmitted between the source and destination using RF and FSO l...

  • Review
  • Open Access
8 Citations
6,096 Views
46 Pages

24 May 2025

As sensor technology integrates into modern life, diverse sensing devices have become essential for collecting critical data that enables human–machine interfaces such as autonomous vehicles and healthcare monitoring systems. However, the growi...

  • Article
  • Open Access
5 Citations
2,211 Views
10 Pages

Recently, atmospheric-turbulence-induced fading in free-space optical (FSO) communication with pointing error impairment was modeled and studied using the Fisher–Snedecor F distribution with a good fit to experimental data. In this letter, we i...

  • Article
  • Open Access
13 Citations
3,842 Views
20 Pages

Integrated Sensor-Optics Communication System Using Bidirectional Fiber and FSO Channels and Hybrid Deep Learning Techniques

  • Amare Mulatie Dehnaw,
  • Yibeltal Chanie Manie,
  • Li-Yuan Du,
  • Cheng-Kai Yao,
  • Jun-Wei Jiang,
  • Bing-Xian Liu and
  • Peng-Chun Peng

13 October 2023

This paper introduces a new bidirectional integration approach that combines fiber sensor/free space optics (FSO) communication using an intensity and wavelength division multiplexer (IWDM) techniques-based long-distance fiber Bragg grating (FBG) sen...

  • Article
  • Open Access
2 Citations
1,768 Views
15 Pages

Propagation Properties of Partially Coherent Flat-Topped Beam Rectangular Arrays in Plasma and Atmospheric Turbulence

  • Xinkai Ma,
  • Hui Zhang,
  • Yuanhao Zhao,
  • LinXuan Yao,
  • Changchun Yu,
  • Yaru Gao,
  • Yangsheng Yuan,
  • Yangjian Cai and
  • Bohan Guo

19 January 2025

Propagation properties represent a critical aspect of laser beams utilized in free space optical (FSO) communications. We examined the evolution characteristics of the electric field associated with partially coherent flat-topped beam rectangular arr...

  • Article
  • Open Access
3 Citations
874 Views
18 Pages

28 February 2025

Next-generation passive optical networks (NG-PONs) are considered an essential solution for optical architectures, owing to the benefits of energy savings, service transparency, supporting several subscribers, and cost-effectiveness. In this work, a...

  • Article
  • Open Access
12 Citations
3,631 Views
11 Pages

Performance of SIMO FSO Links over Mixture Composite Irradiance Channels

  • Nikolaos A. Androutsos,
  • Hector E. Nistazakis,
  • Argyris N. Stassinakis,
  • Harilaos G. Sandalidis and
  • George S. Tombras

20 May 2019

Free space optics (FSO) technology has demonstrated an increasingly scientific and commercial interest over the past few years. However, due to signal propagation in the atmosphere, the operation depends strongly on the atmospheric conditions and som...

  • Article
  • Open Access
15 Citations
4,660 Views
25 Pages

Fronthaul Design for Wireless Networks

  • Ivo Sousa,
  • Nuno Sousa,
  • Maria Paula Queluz and
  • António Rodrigues

10 July 2020

Cloud Radio Access Network (C-RAN) architectures have arisen as an alternative to traditional wireless network architectures, notably by taking advantage of the functional split between the multiple distributed Remote Radio Heads (RRHs) and the centr...

  • Article
  • Open Access
407 Views
16 Pages

An FSO System Based on Mirrors for Early Warning of Frost: Primary Analysis

  • Sarah Alsarayreh,
  • Rula Alrawashdeh and
  • Jiafeng Zhou

5 December 2025

This paper proposes a free-space optical (FSO) system for early warning and detection of natural disasters. The system consists of multiple sensor nodes equipped with mirrors, motors, and controllers. Under normal weather conditions, signals are tran...

  • Article
  • Open Access
7 Citations
2,880 Views
11 Pages

In this paper, we study a mixed cooperative communication system consisting of power line communication (PLC) and free-space optical communication (FSO) links, where the PLC link suffers from log-normal fading and is affected by both impulsive and ba...

  • Article
  • Open Access
19 Citations
5,314 Views
17 Pages

Recently, a combination of unmanned aerial vehicles (UAVs) and free-space optics (FSO) has been investigated as a potential method for high data-rate front-haul communication links. The aim of this work was to address the performance of UAV-to-ground...

  • Article
  • Open Access
2,087 Views
22 Pages

Performance Analysis of UAV-IRS Relay Multi-Hop FSO/THz Link

  • Yawei Wang,
  • Rongpeng Liu,
  • Jia Yuan,
  • Jingwei Lu,
  • Ziyang Wang,
  • Ruihuan Wu,
  • Zhongchao Wei and
  • Hongzhan Liu

15 August 2024

As the era of sixth-generation (6G) communications approaches, there will be an unprecedented increase in the number of wireless internet-connected devices and a sharp rise in mobile data traffic. Faced with the scarcity of spectrum resources in trad...

  • Feature Paper
  • Article
  • Open Access
36 Citations
3,557 Views
16 Pages

Experimental Performance Analysis of an Optical Communication Channel over Maritime Environment

  • Antonios Lionis,
  • Konstantinos Peppas,
  • Hector E. Nistazakis,
  • Andreas D. Tsigopoulos and
  • Keith Cohn

Free space optical communications (FSO), which make use of the visible and infrared spectrum for data transmission, offer significant advantages such as a very high data rate, security and immunity, low cost of installation and ease of use without an...

  • Article
  • Open Access
6 Citations
2,855 Views
20 Pages

20 February 2024

The unmanned aerial vehicle (UAV) communication network has emerged as a promising paradigm capable of independent operation and as a relay to enhance communication coverage and efficiency. However, densely distributed terrestrial base stations with...

  • Article
  • Open Access
5 Citations
4,390 Views
18 Pages

Low Power FPGA Implementation of a Smart Building Free Space Optical Communication System

  • Rehab Ali,
  • Hossameldin Eassa,
  • Hesham H. Aly,
  • Mohamed Abaza and
  • Saleh M. Eisa

Free Space Optical (FSO) communication systems have extensively invaded the speed of smart city evolution due to the current surge in demand for wireless communication spots that can match recent challenges due to high technical leaps in smart city e...

  • Article
  • Open Access
22 Citations
2,884 Views
16 Pages

High-Capacity Free Space Optics-Based Passive Optical Network for 5G Front-Haul Deployment

  • Rahat Ullah,
  • Sibghat Ullah,
  • Waqas A. Imtiaz,
  • Jahangir Khan,
  • Peer Meher Ali Shah,
  • Muhammad Kamran,
  • Jianxin Ren and
  • Shuaidong Chen

24 September 2023

With the expansion of Information and Communication Technology, it is important to develop a communication network that can provide high-capacity ubiquitous connectivity. This work proposes an energy-efficient passive optical network (PON) using orth...

  • Article
  • Open Access
13 Citations
4,158 Views
23 Pages

19 January 2023

Free-space optical (FSO) communication is expected to play an indispensable role with high data rates and low system complexity in beyond fifth-generation (B5G) networks. However, infrequent adverse weather conditions can incapacitate its performance...

  • Article
  • Open Access
1,166 Views
24 Pages

Performance Study of FSO/THz Dual-Hop System Based on Cognitive Radio and Energy Harvesting System

  • Jingwei Lu,
  • Rongpeng Liu,
  • Yawei Wang,
  • Ziyang Wang and
  • Hongzhan Liu

26 November 2024

In order to address the problems of low spectrum efficiency in current communication systems and extend the lifetime of energy-constrained relay devices, this paper proposes a novel dual-hop free-space optical (FSO) system that integrates cognitive r...

  • Article
  • Open Access
4 Citations
5,569 Views
14 Pages

16 October 2015

This paper presents a novel model of heterodyne-detected optical code-division multiple-access (OCDMA) systems employing polarization shift keying (PolSK) modulation over a free-space optical (FSO) turbulence channel. In this article, a new transceiv...

  • Article
  • Open Access
13 Citations
5,138 Views
15 Pages

30 April 2022

Coherent detection provides the optimum performance for free space optical (FSO) communication systems. However, such detection systems are expensive and require digital phase noise compensation. In this paper, the transmission performance of long-ha...

  • Article
  • Open Access
4 Citations
1,896 Views
13 Pages

Performance Analysis of Soft-Switching FSO/THz-RF Dual-Hop AF-NOMA Link Based on Cognitive Radio

  • Rongpeng Liu,
  • Ziyang Wang,
  • Xuerui Wang,
  • Jingwei Lu,
  • Yawei Wang,
  • Yizhou Zhuo,
  • Ruihuan Wu,
  • Zhongchao Wei and
  • Hongzhan Liu

27 September 2023

This paper presents a promising solution to address the scarcity of spectrum resources and enhance spectrum efficiency in the context of cognitive radio (CR)-based soft-switching free-space optical (FSO)/terahertz (THz) radio frequency (RF) dual-hop...

  • Communication
  • Open Access
258 Views
14 Pages

15 December 2025

We experimentally demonstrate an 80 Gbit/s Nyquist-dense wavelength division multiplexed (Nyquist-DWDM) transmission system operating in a simulated atmospheric turbulence channel. The system utilizes eight wavelength-tunable lasers with 100 GHz spac...

  • Article
  • Open Access
8 Citations
3,861 Views
16 Pages

A Novel System of Mixed RF/FSO UAV Communication Based on MRR and RIS by Adopting Hybrid Modulation

  • Jia Yuan,
  • Xiaoyi Wang,
  • Meng Jin,
  • Wenyi Liu,
  • Ruihuan Wu,
  • Zhongchao Wei,
  • Dongmei Deng and
  • Hongzhan Liu

In this paper, we propose a mixed radio frequency (RF)/free space optical (FSO) unmanned aerial vehicle (UAV) communication system, based on modulating retro-reflector (MRR) and reconfigurable intelligent surface (RIS), which adopts the hybrid L-ary...

  • Review
  • Open Access
10 Citations
6,772 Views
25 Pages

A Review of Variable-Beam Divergence Angle FSO Communication Systems

  • Guoqiang Zhang,
  • Jiabin Wu,
  • Yatian Li,
  • Ximing Wang,
  • Xichang Yu,
  • Shijie Gao and
  • Lie Ma

Free-space optical (FSO) communication is widely used in satellites, ships, aircraft, and ground stations due to its advantages of high speed, large capacity, good confidentiality, and strong anti-interference ability. Variable-beam divergence angle...

  • Article
  • Open Access
22 Citations
4,023 Views
15 Pages

DF Relayed Subcarrier FSO Links over Malaga Turbulence Channels with Phase Noise and Non-Zero Boresight Pointing Errors

  • George K. Varotsos,
  • Hector E. Nistazakis,
  • Wilfried Gappmair,
  • Harilaos G. Sandalidis and
  • George S. Tombras

25 April 2018

Subcarrier free-space optical (FSO) systems using coherent recovery techniques at the receiver have acquired growing research interest in recent times. However, their optimal performance is diminished by the non-perfect synchronization of carrier fre...

  • Article
  • Open Access
1,703 Views
17 Pages

22 April 2025

Free space optics (FSOs) is an emerging technology offering solutions for secure and high data rate transmission in dense urban areas, back haul link in telecommunication networks, and last mile access applications. It is important to investigate the...

  • Article
  • Open Access
918 Views
13 Pages

Concentric Intensity-Based Adjacent OAM Mode Separation for High-Efficiency Free-Space Optical Spatial Multiplexing

  • Ji-Yung Lee,
  • Jiyeon Baek,
  • Junsu Kim,
  • Sujan Rajbhandari,
  • Seung Ryong Park and
  • Hyunchae Chun

13 August 2025

The rapid growth of data traffic in modern communication networks has led to the development of advanced high-capacity multiplexing methods. Orbital angular momentum (OAM)–based mode division multiplexing (MDM) offers a promising scheme by util...

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