Investigations on hybrid wavelength-mode-orthogonal frequency-division multiplexing scheme based free space optical transmission system under varying atmospheric conditions

Joseph, Deepthi; Karthikeyan, A.; Kuppusamy, P.; Prabhu, V.

doi:10.1007/s11082-021-03456-z

Cited by 8 publications

(2 citation statements)

References 37 publications

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“…The LOS-UOWC channel in Figure 2c can be modeled using the equation below, as in the case of [3,[43][44][45][46]. The level of optical power received P r depends on the optical power transmitted by the laser diode P t ; the transmitter and receiver optical efficiencies η t and η r , respectively; the angle of the trajectory perpendicular to the transmitter-receiver planes θ; the aperture area of photodetector A r ; and the divergence angle of the laser beam θ d [13].…”

Section: Proposed System Modelmentioning

confidence: 99%

“…This phenomenon characterizes the chaotic change in the water flow velocity and pressure, and this turbulence affects the water characteristics when laser light beams propagate underwater. This results in fluctuations in the optical power and degrades the system performance owing to variations in the refractive index of water [22,[46][47][48][49][50][51].…”

Section: Proposed System Modelmentioning

confidence: 99%

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A 930 m/180 Gbps*User Underwater Coherent Optical Code-Division Multiple-Access Network Based on Hybrid 256-Differential Pulse Position Modulation and Weighted Modified Prime Code Sequence

Ismail,

Saleh

2024

Photonics

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Currently, there are three types of optical communication networks based on the communication channel between the transmitter and receiver: the optical fiber channel, visible light channel, and optical wireless channel networks. The last type has several advantages for underwater communication, wireless sensors, and military communication networks. However, this type of optical network suffers from weather conditions in free-space communications and attenuation owing to the scattering and absorption mechanisms for underwater communication. In this study, we present a new transceiver architecture of a coherent optical code-division multiple-access (OCDMA) system based on a hybrid M-ary differential pulse position modulation scheme and a spreading code sequence called weighted modified prime code for underwater communication to minimize channel dispersion, increase the transmission rate per second, enhance the network bit error rate (BER) performance, and improve network security. Using an OCDMA system, we can simultaneously expand the network coverage area and increase the number of users sharing the network over the same channel bandwidth. The simulation results in this study proved that the proposed system can accommodate 1310 active users and a network throughput of 180 Gbps*user over a transmission distance of 930 m without any repeater at a 10−9 BER performance, compared to the 45 Gbps*user network throughput and 100 m transmission distance reported in the literature.

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