Blind Detection for Serial Relays in Free Space Optical Communication Systems

Elbawab, Mohamed; Abaza, Mohamed; Aly, Moustafa H.

doi:10.3390/app8112074

Cited by 5 publications

(4 citation statements)

References 20 publications

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“…Compared with the literature [24] algorithm, the complexity and running time of the proposed algorithm are decreased. Under the above simulation conditions, the number of addition and multiplication [16] algorithm are 1.080 × 10 7 times and 6.516 × 10 6 times and the number of addition and multiplication operations of the proposed method is 8.886 × 10 6 times and 6.276 × 10 6 times, respectively. The addition and multiplication complexity of the proposed scheme is decreased by 21.5% and 3.8%, respectively, and the overall computational complexity of the system decreased by 14.2%.…”

Section: Resultsmentioning

confidence: 99%

“…In [15], for the asymmetric shaping DFDMA (CO-OFDM) system, an algorithm for simultaneously eliminating DCO and system noise is proposed by using the concept of Virtual Clean Window (VCW). The authors in [16] proposed a dual-hop blind detection FSO system over a log-normal channel. The improved CSI is obtained using a relay using such algorithm.…”

Section: Introductionmentioning

confidence: 99%

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An Efficient Method for Offset Mitigation in Free-Space Optical Systems

2019

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Channel estimation is a key feature for free space optical (FSO) wireless communication systems which are required for a high QoS and high data rate system. Aiming at the problem of FSO wireless channel estimation, this paper proposes an implicit sequence channel estimation scheme to eliminate dc offset, and studies the key factors affecting the system performance. The optimal power allocation factor is derived based on the maximum SNR criterion. The system performance parameters such as the bit error rate (BER), mean square error (MSE), and computational complexity are evaluated. The results show that under the same dc bias condition, the MSE is estimated to decrease significantly after using the method of this paper. With the increase of dc offset d, the system error rate is significantly reduced and more approaching d = 0 (i.e., no dc offset). The proposed algorithm effectively mitigates the dc offset impact on the system and the BER is significantly improved while the MSE is reduced to 50% of the traditional state-of-the-art method. The proposed work can provide a technical solution to the FSO system and give support to technological development.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

An Efficient Method for Offset Mitigation in Free-Space Optical Systems

2019

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“…The obtained results show that no optimum technique exists for all channel conditions, and the relay selection algorithm needs to take into account the severity of atmospheric induced fading and the pointing errors. Elbawab, et al [7] have evaluated the performance of a relay-assisted FSO communication system with a blind detection scheme. The authors derive novel analytical expressions for the average bit error rate and demonstrate that this technique performs similar to more complex systems requiring channel state information.…”

Section: Outdoor Systemsmentioning

confidence: 99%

Special Issue on Light Communications: Latest Advances and Prospects

et al. 2022

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“…The authors of [10] have derived the ABER of two steps blind detection system while using a relay. The authors have also advised that the middle of the channel is the best location for the relay.…”

Section: Introductionmentioning

confidence: 99%

Relay Selection Schemes for FSO Communications over Turbulent Channels

et al. 2019

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Free Space Optics (FSO) Communication has attracted the attention of the researchers in the last decade due to its high data rate, security, and low cost. Relay-assisted techniques are used to divide the distance to shorter hops in order to mitigate the effects of turbulence, weather attenuation, pointing error, and geometric loss. Choosing an active relay per time slot has been proven to enhance the performance of the system and decrease the loading effect on the system when compared to all active relays. This paper investigates the best relay that can be selected according to the source to relay (S-R) channel coefficient, relay to destination (R-D) channel coefficient, and source to destination (S-D) channel coefficient. A comprehensive comparison is applied to the three following cases: (a) Broadcast phase from source to relay to select the best (Proactive-Relay); (b) Broadcast phase from relay to destination after broadcasting to all relays then select (Reactive-relays); and, (c) Direct link from source-to-best relay-to-destination to conclude which method is better for different scenarios, such as turbulence regime, number of relays, different pointing error effect, and severity of S-R as compared to R-D and vice versa. The selection methods regard to four aspects: (1) Number of relays (two or three relays); (2) Distance between Source-Relay and Relay-Destination (D = 400–600 m, 500–500 m, and 600–400 m); (3) The different turbulence of Log-normal channel and Gamma-Gamma channel (with a refractive index coefficient( C n 2 = 0.5 × 10−14, 2 × 10−14 and 5 × 10−14)); and finally, (4) Beam waist ω z (pointing error).

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Blind Detection for Serial Relays in Free Space Optical Communication Systems

Cited by 5 publications

References 20 publications

An Efficient Method for Offset Mitigation in Free-Space Optical Systems

An Efficient Method for Offset Mitigation in Free-Space Optical Systems

Special Issue on Light Communications: Latest Advances and Prospects

Relay Selection Schemes for FSO Communications over Turbulent Channels

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