- 标题
- 摘要
- 关键词
- 实验方案
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Performance Evaluation of Hybrid FSO-SACOCDMA System under Different Weather Conditions
摘要： Spectral amplitude coding optical code division multiple access (SACOCDMA) is a multiplexing technique, which provides faster speed, efficiency, security and unlimited bandwidth. It is widely preferred because of its ability to eliminate multiple access interference (MAI). Free space optics (FSO) provides a wireless link to transmit data securely at higher rates for last mile access. In this work, a 100 Gb/s hybrid FSO-SACOCDMA is designed using direct detection. The performance of FSO using SACOCDMA utilizing NZCC (New Zero Cross Correlation) code is evaluated under different weather conditions (clear weather, haze and fog) for ten users where each user carries 10 Gb/s. The results indicate that in clear weather FSO distance can be extended up to 13 km. Moreover, after using pre-amplifier in clear weather, FSO enhances the maximum distance to 35 km with acceptable signal to noise ratio and bit error rate. Using an amplifier in the link not only makes the quality of the signal better but it also increases the communication range.
关键词： spectral amplitude coding optical code division multiple access (SACOCDMA),free space optics (FSO),direct detection (DD),new zero cross correlation (NZCC)
更新于2025-09-23 15:23:52
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[IEEE 2018 International Conference on Intelligent and Innovative Computing Applications (ICONIC) - Mon Tresor, Plaine Magnien, Mauritius (2018.12.6-2018.12.7)] 2018 International Conference on Intelligent and Innovative Computing Applications (ICONIC) - Climatic Effects on Free Space Optics Link: South African Climate
摘要： The growth in demand of high data rate, reliable quality of service, low cost technology and secured connectivity have been telecommunication users' concerns. Free Space Optics (FSO) is the best choice for meeting these demands as it offers data rates in Gbps with the most secure communication because light beam is prone to eavesdropping. However, usage of FSO as a communication link relies upon local weather condition. Atmospheric attenuation of fog, rain and snow are the most limitation of free space optic availability, as they lead to the diminution of limited available bandwidth. This paper investigated the link performance under climatic conditions such as fog, rain and snow by at various wavelengths of 650nm, 750nm, 850nm, 950nm and 1550nm. It is further deals with FSO performance targeting to acquire minimal Bit Error Rate (BER), suitable transmitting power, optimum link margin and reliable data transmission rate at maximum link distance of 1km. The studies observed that received power signal and the link distance have an inverse correlation because once the signal reaches to an extended distance; it faces greater climatic attenuation due to scattering and absorption lessening.
关键词： communication link,Free space optics,atmospheric attenuation,light beam,bit error rate
更新于2025-09-23 15:22:29
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An optimization model for quadratic flow thinning – a traffic protection mechanism for FSO networks
摘要： Flow thinning (FT) is an active traffic protection mechanism destined for communication networks with variable capacity of links, for example wireless networks. In FT, end-to-end traffic demands are equipped with dedicated logical tunnels (for example MPLS tunnels) whose maximal capacities are subject to thinning in order to follow the fluctuations of the currently available link capacities. It follows that for each demand the instantaneous traffic realized between its end nodes must accommodate to the current total capacity available on its dedicated tunnels. In the paper we develop an optimization model for network dimensioning for an applicative modification of FT, the so called Quadratic Flow Thinning (QFT), and present a solution algorithm based on the path generation method. We derive relevant pricing problems for basic variants of the QFT mechanism (and for its special case Affine Flow Thinning, AFT), and present a numerical study that illustrates efficiency of the optimization algorithm, as well as compares the network cost for different variants of QFT and AFT.
关键词： Free space optics,Linear and mixed-integer programming,Resilient networks,Multicommodity flows,Quadratic and affine routing,Variable link capacity,Path generation
更新于2025-09-23 15:22:29
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[IEEE 2018 14th International Wireless Communications & Mobile Computing Conference (IWCMC) - Limassol, Cyprus (2018.6.25-2018.6.29)] 2018 14th International Wireless Communications & Mobile Computing Conference (IWCMC) - Contrasting MISO Schemes for IM/DD FSO Communications with Photon-Counting Receivers
摘要： In this paper, we consider the problem of Multiple-Input-Single-Output (MISO) Free-Space Optical (FSO) communications with intensity-modulation and direct-detection (IM/DD). Unlike the commonly adopted Gaussian-noise approximation, we adopt the exact Poisson statistics for the number of photons falling on the receiver. In particular, we compare three popular MISO schemes; namely, repetition coding (RC), optical spatial modulation (OSM) and spatial multiplexing (SMux). For each one of these schemes, we derive the optimal maximum-likelihood (ML) decoder and we contrast the schemes in terms of rate, performance, complexity, channel state information requirements and tolerance to channel estimation errors.
关键词： Free space optics,spatial modulation,maximum likelihood,repetition coding,spatial multiplexing,MIMO
更新于2025-09-23 15:22:29
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[IEEE 2018 International Conference on Information and Communication Technology Convergence (ICTC) - Jeju (2018.10.17-2018.10.19)] 2018 International Conference on Information and Communication Technology Convergence (ICTC) - Performance of SIM/S-QAM FSO Systems with Phase Errors in Gamma-Gamma Turbulence Channels
摘要： In this paper, we study the performance of subcarrier intensity modulation (SIM) squared quadrature-amplitude modulation (S-QAM) free-space optical (FSO) communication systems considering the atmospheric turbulence-induced phase error in fading channel. The atmospheric fading channel is modeled by Gamma-Gamma distribution while the Tikhonov model is used for the turbulence-induced phase error. The numerical results quantitatively show the impact of atmospheric turbulence parameters to the performance of FSO systems in terms of average symbol-error probability (ASEP) and the power penalty. Besides, the theoretical results are validated through Monte Carlo simulation to confirm our analysis.
关键词： Free-space optics (FSO),Phase error.,Atmospheric Turbulence,Fading Channel,Squared quadrature-amplitude modulation (QAM)
更新于2025-09-23 15:22:29
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[IEEE 2018 Second International Conference on Electronics, Communication and Aerospace Technology (ICECA) - Coimbatore (2018.3.29-2018.3.31)] 2018 Second International Conference on Electronics, Communication and Aerospace Technology (ICECA) - FSO Link Performance Analysis with Different Modulation Techniques under Atmospheric Turbulence
摘要： Free space optics (FSO) has achieved prominence in extremely large bandwidth, unlicensed spectrum and low power secure transmission in the field of wireless communication. Despite the advantages, it is deeply impacted due to atmospheric turbulence and fog weather conditions. This paper considers different modulation schemes under the presence of atmospheric turbulence and fog conditions. The desired expression of bit error rate (BER) is obtained by modeling the turbulence as gamma-gamma distributed channel and under this channel condition, 16-PPM has provided better performance than other schemes. BER is considered for the channel performance evaluation. This analysis can help to adopt a modulation technique according to the channel condition.
关键词： Bit error rate (BER),gamma-gamma distribution,atmospheric turbulence,Free space optics (FSO),Meijer’s G function
更新于2025-09-23 15:21:21
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IEEE Access Special Section Editorial: Optical Wireless Technologies for 5G Communications and Beyond
摘要： Wide bandwidth and dense spatial reuse are of extreme importance for future wireless communication networks, including 5G and beyond. In particular, these properties are important to enable future wireless networks to cope with the explosive increase in the demand for high data-rate communications. Optical wireless communications (OWC) is a promising technology for achieving this goal due to the abundant reusable license-free optical spectrum. This potential of OWC attracted significant global attention both from communications and optoelectronics viewpoints, and continues to do so.
关键词： 5G,beam-steering,mixed FSO/fiber backhauling,OFDM,MIMO,Optical wireless communications,vehicle-to-vehicle communications,free-space optics,vehicle-to-infrastructure communications,network-layer aspects,visible-light communications
更新于2025-09-23 15:21:21
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Demonstration of a Hybrid FSO/VLC Link for the Last Mile and Last Meter Networks
摘要： In this paper, a hybrid free-space optical and visible light communication (FSO/VLC) system was experimentally demonstrated as a solution to overcome the last mile and last meter access networks bandwidth bottleneck. We evaluate the system performance of a multiband carrier-less amplitude and phase (m-CAP) modulation scheme for a range of FSO/VLC link lengths and m-CAP parameters (i.e., the roll-off factor of the ?lters and a number of subcarriers) in terms of the data rate Rb (i.e., spectral ef?ciency). We show that for the con?guration with a 1 m VLC link the 10-CAP offers more than a 40 % improvement in the measured Rb compared to 2-CAP for the same bit error rate target. The Rb penalty due to the extension of a VLC link span from 1 m to 3 m reaches to 12.6 Mb/s for the 10-CAP scheme (i.e., ～39 % degradation in Rb). To fully cover all aspects of the hybrid FSO/VLC system, we also investigate the atmospheric turbulence effect on the 500 m FSO link n of 2.4×10?15 m?2/3 where Rb is decreased by 30 % for the refractive index structure parameter C2 compared to a clear channel condition.
关键词： multiband carrier-less amplitude and phase modulation,Visible light communication,free space optics
更新于2025-09-23 15:19:57
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Demonstration of a hybrid optical fibera??wireless 5G fronthaul coexisting with end-to-end 4G networks
摘要： The plethora of services envisaged to support 5G use-cases requires the development of a radio access network (RAN) infrastructure with the capability to integrate a variety of user-demanded mobile traffic characteristics. It is therefore interesting to study a 5G deployment scenario showcasing heterogeneous transmission. In order to address this challenge, in this paper, we propose and experimentally assess a coarse-wavelength-division-multiplexing-compatible optical access network for joint provisioning of 4G/5G RAN services, supporting the coexistence of both digital and analog radio-over-fiber (ARoF) fronthauling. Resorting to an integrated testbed, we demonstrate the transport of 100 MHz 5G downlink using low-latency and bandwidth-efficient ARoF over 8 km fiber, seamlessly coexisting on the same fronthaul infrastructure with a legacy full-fledged 4G long-term evolution (LTE) network supported by Ethernet-based digital RoF with different functional splits. In addition, we experimentally demonstrate the successful operation of the 4G/5G system in a hybrid fiber–wireless scenario including a free-space optics fronthaul extension with 55 m. The proposed heterogeneous RAN architecture is demonstrated to provide a flexible and robust integration path for novel 5G technologies, enabling their coexistence with currently deployed 4G LTE systems over a shared fronthaul infrastructure.
关键词： free-space optics,fronthaul,radio access network,5G,4G LTE,digital radio-over-fiber,analog radio-over-fiber
更新于2025-09-19 17:13:59
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[IEEE 2019 18th International Conference on Optical Communications and Networks (ICOCN) - Huangshan, China (2019.8.5-2019.8.8)] 2019 18th International Conference on Optical Communications and Networks (ICOCN) - An Optical Communication System Adjusting Method for GEO Satellites
摘要： In this paper, we proposed an optical communication system adjusting method for the geostationary-earth-orbit (GEO) satellites. The proposal is demonstrated and evaluated by theoretical analysis and experiments. It is able to guarantee not only the coherent detection communications among the GEO satellites but also the direct detection communications between the GEO satellite and the low-earth-orbit (LEO) satellite.
关键词： System Adjusting Method,LEO Satellites,Free Space Optics (FSO),GEO Satellites
更新于2025-09-16 10:30:52