SAC-OCDMA-FSO communication system under different weather conditions: performance enhancement

El-Mottaleb, Somia A. Abd; Métwalli, Ahmed; Hassib, Mostafa; Alfikky, Abdelrahman A.; Fayed, Heba A.; Aly, Moustafa H.

doi:10.1007/s11082-021-03269-0

Cited by 35 publications

(34 citation statements)

References 19 publications

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“…It can be seen that AT and PEs effect the BER with different severity. For example, heavy weather turbulence degrades the SNR and raises the BER [33,34]. As far as AT and PEs are concerned, they affect BER equally.…”

Section: Numerical Results and Discussionmentioning

confidence: 99%

Performance enhancement of UAV relay-assisted free-space optics systems with pointing errors

Elsayed

Hayal

Kakati

et al. 2022

Preprint

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This paper investigates and enhances unmanned aerial vehicle (UAV) relay-assisted free-space optics (FSO) communication systems under the effects of pointing errors (PEs) and atmospheric turbulences. The incorporation of UAVs as buffer-aided moving relays in the conventional FSO (CFSO) relay-assisted systems is proposed for enhancing the performance of PEs through AT. Using M-PSK (phase shift keying) and M-QAM (quadrature amplitude modulation), the impact of PEs on transmission quality is evaluated in this work. We examine and enhance the symbol error rate, outage probability (OP), and signal-to-noise ratio (SNR) for the UAV-to-ground stationbased FSO communications systems. The spatial diversity-based relay-assisted CFSO systems can enhance the performance of the UAV-UAV FSO links. Numerical results show that to achieve a bit-error-rate (BER) of ≤ 10-5 , the required SNR is ≥ 23 dB when the wind variance of the UAVs 𝜎𝛼2 increases from 0 to 7 mrad with FSO link distance L = 2000 m. The required SNR is ≥ 25 dB when the wind variance 𝜎𝛼2 is 1 mrad at a OP of 10-6 . To obtain an average BER of 10−6 , the SNR should be 16.23 dB, 17.64 dB, and 21.45 dB when 𝜎𝛼2 is 0 mrad, 1 mrad, and 2 mrad, respectively. Using 8-PSK modulation without PEs requires 23.5 dB at BER of 10-8 while 16-QAM without PEs requires 26.5 dB to maintain the same BER of 10-8 . Compared with 16-QAM without PEs, the SNR gain of 8-PSK without PEs is 3 dB.

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Section: Numerical Results and Discussionmentioning

confidence: 99%

Performance enhancement of UAV relay-assisted free-space optics systems with pointing errors

Elsayed

Hayal

Kakati

et al. 2022

Preprint

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“…As the adverse climate affects the signal during transmission causing so, the signal-to-noise ratio (SNR) is reduced and the BER is increased. SNR is the ratio of mean signal power, (P u ) 2 , to different noise source's power and is expressed as [24,37,38]…”

Section: Performance Analysismentioning

confidence: 99%

“…Each user is assigned with unique code in SAC-OCDMA. Many codes are used in SAC-OCDMA systems, some of them have zero cross correlations which are difficult to implement such as zero cross correlation (ZCC) [21], multi diagonal [22], and random diagonal (RD) [23], whereas others have unity cross correlation such as enhanced double weight code (EDW) [24]. Unfortunately, the presence of multiple access interference (MAI) in SAC-OCDMA degrades system performance significantly, which may be alleviated by employing an appropriate detection technology (i.e., single photodiode detection technique (SPD)) [24].…”

Section: Introductionmentioning

confidence: 99%

Design of a High-Speed OFDM-SAC-OCDMA-Based FSO System Using EDW Codes for Supporting 5G Data Services and Smart City Applications

Singh

Kříž²,

Kamruzzaman³

et al. 2022

Front. Phys.

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A novel free space optics (FSO) system is introduced in this article by combining orthogonal frequency division multiplexing (OFDM) with spectral amplitude coding optical code division multiple access (SAC-OCDMA) to be implemented in 5G technology and smart cities. Enhanced double-weight (EDW) codes are used as signature codes, while for the detection technique, single photodiode detection (SPD) is applied for the SAC-OCDMA system. OFDM with a four-quadrature amplitude modulation (4-QAM) scheme is assigned to the three users in the SAC-OCDMA system, each carrying 15 Gbps. Adverse weather conditions, such as clear, fog, haze, rain, and dust storm, that affect the FSO channel are considered. The performance of the proposed system is evaluated in terms of log of bit error rate and received power at different propagation distances. The simulation results show successful transmission of 3 × 15 Gbps with a propagation range of 3.45 km under clear air and 1.316, 1.045, and 0.7 km under rain conditions (light, medium, and heavy rain) with a received power of −12.6 dBm. As for haze conditions, the range and received power are 2.391 km with −13 dBm for low haze, 1.591 km with −12.7 dBm for medium haze, and 1.025 km with −12.6 dBm for heavy haze. The range is reduced and becomes 1.085, 0.784, and 0.645 km under fog conditions (light, medium, and heavy fog) with −12.6 dBm received power. Furthermore, the system achieved a range of 0.681, 0.232, and 0.102 km under dust conditions (light, medium, and heavy dust) with a received power of −16 dBm.

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“…The DPS code property when SPD detection is used as where w PD is the number of "1′s" that reach PD and is equal to w + 1. The average received optical power, P u , by the PD for the desired channel with SPD detection is Abd El-Mottaleb et al (2021) where ℜ is the PD responsivity.…”

Section: Performance Analysismentioning

confidence: 99%

“…Thermal noise, Th N , can be expressed as Abd El-Mottaleb et al (2021) where k B is Boltzmann constant, T n is the receiver noise absolute temperature, and R L is the receiver load resistance.…”

Section: Performance Analysismentioning

confidence: 99%

Performance evaluation of PDM/SAC-OCDMA-FSO communication system using DPS code under fog, dust and rain

et al. 2022

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A new hybrid polarization division multiplexing (PDM) spectral amplitude coding optical code division multiple access (SAC-OCDMA) is proposed for free space optical (FSO) for capacity enhancement. Two polarization signals are utilized; one is x-polarization and carries three different channels at 0° azimuthal angle while the other is y-polarization at 90° azimuthal angle, and carries the same three channels. Each channel is assigned with a diagonal permutation shift (DPS) code and carries 10 Gbps. The suggested system is simulated, and its performance is evaluated in terms of maximum allowable number of users, propagation range, bit error rate (BER), Q-factor, and received power for the different channels under various fog, dust storm, and rain scenarios. The reported results indicate that the system can support a signal travelling up to 2, 0.9, and 1.3 km, respectively, under light fog (LF), light dust (LD), and light rain (LR). As the level of these weather conditions is increased from light to moderate, the FSO link length decreases to 1.3, 0.25, and 1.8 km under medium fog (MF), medium dust (MD), and medium rain (MR), respectively. Furthermore, the shortest propagation range is achieved as the level of weather conditions becomes heavy, where the FSO link range becomes 1, 0.095, and 1.1 km under heavy fog (HF), heavy dust (HD), and heavy rain (HR), respectively. All these ranges are considered at BER ≤ 10–3 and a received power ≤ − 27 dBm with 60 Gbps overall data transmission. This new hybrid FSO system is suggested to be implemented in desert areas that affects by dust storms and in 5G wireless transmission communications.

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SAC-OCDMA-FSO communication system under different weather conditions: performance enhancement

Cited by 35 publications

References 19 publications

Performance enhancement of UAV relay-assisted free-space optics systems with pointing errors

Performance enhancement of UAV relay-assisted free-space optics systems with pointing errors

Design of a High-Speed OFDM-SAC-OCDMA-Based FSO System Using EDW Codes for Supporting 5G Data Services and Smart City Applications

Performance evaluation of PDM/SAC-OCDMA-FSO communication system using DPS code under fog, dust and rain

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