BER of an optically pre-amplified FSO system under Málaga turbulence, pointing errors, and ASE noise
01 Oct 2017-pp 1-6
TL;DR: The bit error rate (BER) performance of a FSO system assuming non-return-to-zero on-off keying modulation in the presence of ASE noise under M-turbulence and PEs is evaluated.
Abstract: The performance of a free space optical (FSO) communication system is significantly affected by atmospheric turbulence and pointing errors (PEs) apart from the additive noise which is assumed to be Gaussian. The Malaga or M-distribution encompasses various proposed statistical models for atmospheric turbulence in FSO systems. An optical pre-amplifier is an essential component of FSO systems for improving the receiver (Rx) sensitivity. However, optical pre-amplification results in amplified spontaneous emissions (ASE), which dominate the Rx thermal and shot noises. The square law photodetection process at the Rx in a FSO system necessitates the consideration of Chi-square statistics for the decision variable contrary to the Gaussian approximation that is widely used in the literature. In this paper, we evaluate the bit error rate (BER) performance of a FSO system assuming non-return-to-zero on-off keying modulation in the presence of ASE noise under M-turbulence and PEs. We also derive asymptotic BER expressions for the considered FSO system for large values of signal-to-noise ratio in terms of simple elementary functions. A further insight into the system is provided by performing the diversity analysis.
Citations
More filters
TL;DR: The physical layer secrecy performance of a hybrid satellite and free-space optical (FSO) cooperative system is studied and it is found that with the AF with fixed gain scheme, the secrecy diversity order of the investigated system is only dependent on the channel characteristics of the FSO link and theFSO detection type, whereas the secrecy Diversity is zero when the relay node employs DF or AF with variable-gain schemes.
Abstract: In this paper, we study the physical layer secrecy performance of a hybrid satellite and free-space optical (FSO) cooperative system. The satellite links are assumed to follow the shadowed-Rician fading distribution, and the channel of the terrestrial link between the relay and destination is assumed to experience the gamma-gamma fading. For the FSO communications, the effects of different types of detection techniques (i.e., heterodyne detection and intensity modulation with direct detection) as well as the pointing error are considered. We derive exact analytical expressions for the average secrecy capacity and secrecy outage probability (SOP) for both cases of amplify-and-forward (AF) and decode-and-forward (DF) relaying. The asymptotic analysis for the SOP is also conducted to provide more insights on the impact of FSO and satellite channels on secrecy performance. It is found that with the AF with fixed gain scheme, the secrecy diversity order of the investigated system is only dependent on the channel characteristics of the FSO link and the FSO detection type, whereas the secrecy diversity is zero when the relay node employs DF or AF with variable-gain schemes.
104 citations
Cites methods from "BER of an optically pre-amplified F..."
...Remark 1: It is worth mentioning that another widely used distribution to model the FSO link is the Málaga model [25], [26]....
[...]
TL;DR: It is shown analytically that, both correlation and pre-amplification do not affect the diversity order of the system, however, both factors have contrasting behaviour with respect to coding gain.
Abstract: This paper presents theoretical and experimental bit error rate (BER) results for a free-space optical (FSO) multiple-input-multiple-output system over an arbitrarily correlated turbulence channel. We employ an erbium-doped fiber amplifier at the receiver (Rx), which results in an improved Rx’s sensitivity at the cost of an additional non-Gaussian amplified spontaneous emission noise. Repetition coding is used to combat turbulence and to improve the BER performance of the FSO links. A mathematical framework is provided for the considered FSO system over a correlated non-identically distributed Gamma-Gamma channel; and analytical BER results are derived with and without the pre-amplifier for a comparative study. Moreover, novel closed-form expressions for the asymptotic BER are derived; a comprehensive discussion about the diversity order and coding gain is presented by performing asymptotic analysis at high signal-to-noise ratio (SNR). To verify the analytical results, an experimental set-up of a $2\times 1$ FSO-multiple-input-single-output (MISO) system with pre-amplifier at the Rx is developed. It is shown analytically that, both correlation and pre-amplification do not affect the diversity order of the system, however, both factors have contrasting behaviour with respect to coding gain. Further, to achieve the target forward error correction BER limit of $3.8\times 10^{-3}$ , a $2\times 1$ FSO-MISO system with a pre-amplifier requires 6.5 dB lower SNR compared with the system with no pre-amplifier. Moreover, an SNR penalty of 2.5 dB is incurred at a higher correlation level for the developed $2\times 1$ experimental FSO set-up, which is in agreement with the analytical findings.
10 citations
Cites methods from "BER of an optically pre-amplified F..."
...The authors in [24]–[27] studied the effect of turbulence and pointing error on the BER performance of an optically pre-amplified FSO system by considering different distributions to model the FSO channel....
[...]
TL;DR: Based on the working principle of the photoelectric detector in atmospheric turbulence, an optical communication receiving system based on the detector gain factor regulation control is designed, which calculates the scintillation variance according to the received signal in real-time, establishes the function conversion relationship between the SCI variance and the gain factor, realizes the closed-loop regulation control of the detector, and improves the SNR of the receiving system as discussed by the authors.
Abstract: Space laser communication, with its strong anti-jamming capability, high transmission rate and good adaptability, offers hope for the establishment of 5G mobile networks in areas that are not conducive to the erection of cables, such as islands and remote land areas. Turbulent scintillation effect is one of the important factors affecting the performance of laser communication, which can lead to the increase of communication BER and even communication interruption. Based on the working principle of the photoelectric detector in atmospheric turbulence, an optical communication receiving system based on the detector gain factor regulation control is designed, which calculates the scintillation variance according to the received signal in real time, establishes the function conversion relationship between the scintillation variance and the gain factor, realizes the closed-loop regulation control of the detector gain factor, and improves the SNR of the receiving system. A ground-based 13km static laser communication experiment was set up to test the reception performance, and the test results show that the system reduces the communication BER by more than two orders of magnitude and can be kept at 1E-6 under medium to weak turbulence (discriminated by flash variance) at a communication rate of 2.5Gbps. The technology was applied to the test of laser 5G signal transmission between the airship and the ground, and for the first time, the mobile communication (access network) signal transmission with a downlink speed of 1.230Gbps and an uplink speed of 76.4Mbps is realized, which verified the performance of mobile signal transmission between the mobile base station and the fixed station on the ground.
References
More filters
Book•
01 Jan 1943TL;DR: Combinations involving trigonometric and hyperbolic functions and power 5 Indefinite Integrals of Special Functions 6 Definite Integral Integral Functions 7.Associated Legendre Functions 8 Special Functions 9 Hypergeometric Functions 10 Vector Field Theory 11 Algebraic Inequalities 12 Integral Inequality 13 Matrices and related results 14 Determinants 15 Norms 16 Ordinary differential equations 17 Fourier, Laplace, and Mellin Transforms 18 The z-transform
Abstract: 0 Introduction 1 Elementary Functions 2 Indefinite Integrals of Elementary Functions 3 Definite Integrals of Elementary Functions 4.Combinations involving trigonometric and hyperbolic functions and power 5 Indefinite Integrals of Special Functions 6 Definite Integrals of Special Functions 7.Associated Legendre Functions 8 Special Functions 9 Hypergeometric Functions 10 Vector Field Theory 11 Algebraic Inequalities 12 Integral Inequalities 13 Matrices and related results 14 Determinants 15 Norms 16 Ordinary differential equations 17 Fourier, Laplace, and Mellin Transforms 18 The z-transform
27,354 citations
Book•
01 Jan 1970
17,608 citations
TL;DR: Some of the exciting new research approaches that have been suggested to deal with UOWC issues are presented, including optimization of telescope gain, new technologies for pointing systems, and solutions at the network level.
Abstract: Urban optical wireless communication (UOWC) is rapidly gaining popularity as an effective means of transferring data at high rates over short distances The UOWC terminal includes an optical transmitter and a receiver positioned, for example, on high-rise buildings separated by several hundred meters Light beams propagating through the atmosphere carry the information from the transmitter to the receiver UOWC boasts many advantages over its rivals Notably, UOWC facilitates rapidly deployable, lightweight, high-capacity communication without licensing fees and tariffs However, UOWC still faces many challenges, including how to improve communication performance in adverse weather conditions or during building sway We present and evaluate some of the exciting new research approaches that have been suggested to deal with these issues, including optimization of telescope gain, new technologies for pointing systems, and solutions at the network level
586 citations
"BER of an optically pre-amplified F..." refers background in this paper
...Free space optical (FSO) communications has garnered significant attention of the research community owing to its numerous benefits such as high modulation bandwidth, unlicensed spectrum, low cost of installation and operation, no health hazards due to non-ionizing radiation, and inherently secure transmission [1]–[3]....
[...]
TL;DR: In this paper, the performance of optical amplifiers and a wideband optical filter is evaluated in the presence of spontaneous noise and photodetector shot noise and compared with those predicted by Gaussian approximations for amplitude shift keying (ASK), Frequency Shift Kening (FSK), or differential phase shift keening (DPSK) modulations.
Abstract: The problem of evaluating the performances of communication systems with optical amplifiers and a wideband optical filter is addressed. Exact probability of error expressions for optical signals in presence of amplifier spontaneous noise and photodetector shot noise are given and compared with those predicted by Gaussian approximations for amplitude shift keying (ASK), frequency shift keying (FSK), or differential phase shift keying (DPSK) modulations, both for ideal photodetectors and for the case where shot noise is significant. >
521 citations
"BER of an optically pre-amplified F..." refers background in this paper
...for modeling the received signal statistics has also been highlighted in [18]–[20], [22]....
[...]
...The bit error rate (BER) of a light wave system with OPAs was evaluated in [18]....
[...]
...The information signal with the energy E is represented in the same basis as ∑2M i=1 siφi(t) with E = ∑2M i=1 s 2 i [18]....
[...]
...where N0 = Nsphf(G− 1) is the noise power spectral density, h is the Planck’s constant, f is the frequency of interest, G is the OPA gain, Nsp is an imperfection factor with value unity, E is the bit energy, 2M is the number of degrees of freedom, and Iν(⋅) is the modified Bessel function of first kind and order ν [18]–[20], [22]....
[...]
...) of the decision variable is assumed to follow the non-central Chi-square distribution in the presence of the transmitted signal; whereas the central Chi-square distribution models the decision variable in the absence of the transmitted signal [18]–[20], [22], [23]....
[...]
TL;DR: In this paper, the error performance of the FSO using a subcarrier intensity modulation (SIM) based on a binary phase shift keying (BPSK) scheme in a clear but turbulent atmosphere is presented.
Abstract: Free-space optical communications (FSO) propagated over a clear atmosphere suffers from irradiance fluctuation caused by small but random atmospheric temperature fluctuations. This results in decreased signal-to-noise ratio (SNR) and consequently impaired performance. In this paper, the error performance of the FSO using a subcarrier intensity modulation (SIM) based on a binary phase shift keying (BPSK) scheme in a clear but turbulent atmosphere is presented. To evaluate the system error performance in turbulence regimes from weak to strong, the probability density function (pdf) of the received irradiance after traversing the atmosphere is modelled using the gamma-gamma distribution while the negative exponential distribution is used to model turbulence in the saturation region and beyond. The effect of turbulence induced irradiance fluctuation is mitigated using spatial diversity at the receiver. With reference to the single photodetector case, up to 12 dB gain in the electrical SNR is predicted with two direct detection PIN photodetectors in strong atmospheric turbulence.
510 citations
"BER of an optically pre-amplified F..." refers background in this paper
...The atmospheric turbulence in FSO systems is characterized by log-normal [5], [6], Gamma-Gamma [7], [8], and negative exponential distribution [9], [10] for weak, moderate to strong, and very strong turbulence regimes....
[...]