Abstract:A closed-form expression for the average capacity of the heterodyne differential phase shift keying (DPSK) free-space optical (FSO) communication systems over gamma-gamma turbulence channels is derived by considering the effect of pointing errors. Numerical results show the average capacity can be evaluated with the effect of atmospheric turbulence conditions, beamwidth and jitter variance. Meanwhile, these results verify the accuracy of our mathematical analysis. This work can be helpful for the heterodyne DP… Show more
“…By placing (2) into (28), to the best of our knowledge, it is not possible to find an exact closed-form solution for the inner integral. On the other hand, if we place (3) into (28), we obtain If an exact closed-form is not obtainable via either (27) and/or (28) and/or (29), the ergodic capacity can be analyzed utilizing the moments.…”
Section: Ergodic Capacity a General Methodologymentioning
confidence: 99%
“…Alternatively, by substituting (4) in (28), the outer integral for LN PDF f L (I a L ) in (28) does not lead to possible exact closed-form results. On the other hand, we have been able to solve the inner integral for zero boresight pointing errors in (28) with (3) to obtain (29) and hence on placing the LN PDF f L (I a L ) (4) into (29), we…”
Section: Ergodic Capacity a General Methodologymentioning
confidence: 99%
“…On the other hand, although we have been able to solve the inner integral for zero boresight pointing errors in (28) with (3) to obtain (29) but on placing the LN PDF f L (I a L ) (4) and the Rician PDF f R (I a R ) (8) into (29), we end up having a double integral. To the best of our knowledge, this double integral does not has an exact closed-form solution nor this double integral can be reduced further to a single integral for other possible solutions.…”
Section: Ergodic Capacity a General Methodologymentioning
“…By placing (2) into (28), to the best of our knowledge, it is not possible to find an exact closed-form solution for the inner integral. On the other hand, if we place (3) into (28), we obtain If an exact closed-form is not obtainable via either (27) and/or (28) and/or (29), the ergodic capacity can be analyzed utilizing the moments.…”
Section: Ergodic Capacity a General Methodologymentioning
confidence: 99%
“…Alternatively, by substituting (4) in (28), the outer integral for LN PDF f L (I a L ) in (28) does not lead to possible exact closed-form results. On the other hand, we have been able to solve the inner integral for zero boresight pointing errors in (28) with (3) to obtain (29) and hence on placing the LN PDF f L (I a L ) (4) into (29), we…”
Section: Ergodic Capacity a General Methodologymentioning
confidence: 99%
“…On the other hand, although we have been able to solve the inner integral for zero boresight pointing errors in (28) with (3) to obtain (29) but on placing the LN PDF f L (I a L ) (4) and the Rician PDF f R (I a R ) (8) into (29), we end up having a double integral. To the best of our knowledge, this double integral does not has an exact closed-form solution nor this double integral can be reduced further to a single integral for other possible solutions.…”
Section: Ergodic Capacity a General Methodologymentioning
“…FSO is emerging as a captivating alternative to work out the hindrances in the connectivity problems. Unlike conventional RF/microwave links, FSO communication systems has huge bandwidth, license-free operation, high security, electromagnetic interference immunity, lower deployment cost and time as compared to conventional RF/microwave links [1]- [4]. The main undignified factor in FSO links is the atmospheric turbulences particularly for long distance communication, more than a few kilometers [5].…”
Abstract-Natural turbulence and scintillation are the major challenges in practical deployment of free space optical (FSO) communication systems. In this paper, a parallel relay assisted FSO system is considered to deal with these challenges. This paper investigates the end-to-end performance of the multihop parallel relay assisted FSO system over a strong atmospheric turbulence channel with misalignment fading. The analysis is carried out for system employing decode-and-forward (DF) relays and for strong turbulence channel which can be modeled by the gamma-gamma distribution. A novel closed-form expression for the outage probability is derived. The results are compared with the direct transmission system. Index Terms-Binary phase shift keying subcarrier intensity modulation, free space optics, outage probability, parallel relay, strong atmospheric turbulence.
I. INTRODUCTIONFree-space optical (FSO) communication uses light propagating in free space to transmit data for telecommunications or computer networking. FSO is emerging as a captivating alternative to work out the hindrances in the connectivity problems. Unlike conventional RF/microwave links, FSO communication systems has huge bandwidth, license-free operation, high security, electromagnetic interference immunity, lower deployment cost and time as compared to conventional RF/microwave links [1]- [4]. The main undignified factor in FSO links is the atmospheric turbulences particularly for long distance communication, more than a few kilometers [5]. Relay assisted FSO system is an effective method to extend coverage and lessen the effects of fading.The two relays assisted schemes broadly used in FSO systems are serial relaying and parallel relaying. The outage probability of serial and parallel relay assisted FSO for log-normal atmospheric turbulence channel with path loss effects by using both decode-and-forward (DF), amplify-and-forward (AF) with K relays is analyzed in [6]. The authors in [7] have studied on the end-to-end performance of serial relay FSO system with AF relays over gamma-gamma channels and employing subcarrier differential phase shift keying modulation (DPSK).The average bit error rate (BER) performance of the DF based cooperative FSO system over gamma-gamma channel using binary phase shift keying (BPSK) based sub-carrier intensity modulation (SIM) is analyzed [8]. In [9], the different DF relay schemes have been introduced to an FSO communication system and their BER performance is investigated in the presence of shot noise, using the photon count method.To the best of the author's knowledge, the outage performance of the multi-hop relaying over the gamma-gamma channel with pointing error using BPSK-SIM has not yet been investigated. In this paper, the outage probability of the DF based parallel relay assisted FSO system is analyzed over the strong atmospheric channel with pointing error using BPSK-SIM.The rest of the paper is organized as follows: Section II discusses the system and channel model used. In Section III, the outage perfo...
In this paper, assuming Intensity-Modulation/Direct Detection (IM/DD) with On-Off Keying (OOK), a novel expression for average BER of FSO over Exponentiated Weibull (EW) atmospheric turbulence channel is derived. In the free space optical (FSO) channel the optical signal suffers from irradiance and phase fluctuations caused by the atmospheric turbulence, which results in Bit Error Rate (BER) performance degradation. We investigate the aperture-averaging effect on BER performance under weak and moderate turbulence regime. In our work we consider EW distribution which is more accurate in the presence of finite-size receiving apertures under weak and moderate turbulence regime.Keywords ─ bit-error rate (BER), on-off keying (OOK), intesity modulation/direct detection (IM/DD), Exponentiated Weibull (EW) distribution, free space optical communication (FSO) , aperture averaging effect.
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