scholarly journals Performance of Multibeam Very High Throughput Satellite Systems Based on FSO Feeder Links with HPA Nonlinearity

2020 ◽  
Author(s):  
Emna Zedini ◽  
Abla Kammoun ◽  
Mohamed-Slim Alouini
Keyword(s):  
Outage Probability ◽  
High Throughput ◽  
Direct Detection ◽  
Satellite Communications ◽  
Ergodic Capacity ◽  
Heterodyne Detection ◽  
High Signal ◽  
Free Space Optical ◽  
Asymptotic Results ◽  
Very High

Due to recent advances in laser satellite communications technology, free-space optical (FSO) links are presented as an ideal alternative to the conventional radio frequency (RF) feeder links of the geostationary satellite for next generation very high throughput satellite (VHTS) systems. In this paper, we investigate the performance of multibeam VHTS systems that account for nonlinear high power amplifiers at the transparent fixed gain satellite transponder. Specifically, we consider the forward link of such systems, where the RF user link is assumed to follow the shadowed Rician model and the FSO feeder link is modeled by the Gamma-Gamma distribution in the presence of beam wander and pointing errors where it operates under either the intensity modulation with direct detection or the heterodyne detection. Moreover, zero-forcing precoder is employed to mitigate the effect of inter-beam interference caused by the aggressive frequency reuse in the user link. The performance of the system under study is evaluated in terms of the outage probability, the average bit-error rate (BER), and the ergodic capacity that are derived in exact closed-forms in terms of the bivariate Meijer's G function. Simple asymptotic results for the outage probability and the average BER are also obtained at high signal-to-noise ratio.

scholarly journals Performance of Multibeam Very High Throughput Satellite Systems Based on FSO Feeder Links with HPA Nonlinearity

2020 ◽  
Author(s):  
Emna Zedini ◽  
Abla Kammoun ◽  
Mohamed-Slim Alouini
Keyword(s):  
Outage Probability ◽  
High Throughput ◽  
Direct Detection ◽  
Satellite Communications ◽  
Ergodic Capacity ◽  
Heterodyne Detection ◽  
High Signal ◽  
Free Space Optical ◽  
Asymptotic Results ◽  
Very High

Due to recent advances in laser satellite communications technology, free-space optical (FSO) links are presented as an ideal alternative to the conventional radio frequency (RF) feeder links of the geostationary satellite for next generation very high throughput satellite (VHTS) systems. In this paper, we investigate the performance of multibeam VHTS systems that account for nonlinear high power amplifiers at the transparent fixed gain satellite transponder. Specifically, we consider the forward link of such systems, where the RF user link is assumed to follow the shadowed Rician model and the FSO feeder link is modeled by the Gamma-Gamma distribution in the presence of beam wander and pointing errors where it operates under either the intensity modulation with direct detection or the heterodyne detection. Moreover, zero-forcing precoder is employed to mitigate the effect of inter-beam interference caused by the aggressive frequency reuse in the user link. The performance of the system under study is evaluated in terms of the outage probability, the average bit-error rate (BER), and the ergodic capacity that are derived in exact closed-forms in terms of the bivariate Meijer's G function. Simple asymptotic results for the outage probability and the average BER are also obtained at high signal-to-noise ratio.

Optical technologies for very high throughput satellite communications

2019 ◽  
Author(s):  
Ramon Mata Calvo ◽  
Juraj Poliak ◽  
Janis Surof ◽  
Andrew Reeves ◽  
Matthias Richerzhagen ◽  
...  
Keyword(s):  
High Throughput ◽  
Satellite Communications ◽  
Very High

scholarly journals Cascaded Rf-Fso-Vlc System using Df Relays

2019 ◽  
Vol 8 (10) ◽  
pp. 4357-4362
Keyword(s):  
Direct Detection ◽  
Detection System ◽  
Signal To Noise Ratio ◽  
Visible Light Communication ◽  
Heterodyne Detection ◽  
Core Network ◽  
Free Space Optical ◽  
Error Performance ◽  
Optical Link ◽  
Detection Techniques

This paper presents performance analysis of cascaded radio frequency-free space optical communication-visible light communication (RF-FSO-VLC) system. The proposed model comprises of the RF link as the core network, a terrestrial optical link for providing last mile connectivity with the indoor cell users communicating through VLC environment. The RF link undergoes Nakagami-m distributed fading, while the terrestrial optical link is modeled by Double Generalized Gamma (DGG) distributed turbulence and Rayleigh-distributed misalignment losses. VLC links are characterized by the randomness in users’ position. Using statistical properties of system signal-to-noise ratio (SNR), outage and error performance of the proposed system is evaluated depending on whether the relays and the destination decode either perfectly or erroneously. The numerical results show that the system performance varies depending on field-of view (FOV) of the detector and user’s position. This is because as FOV increases along with the height of the LED, the outage probability of the system increases. Error probability depends on the type of detection techniques, where a heterodyne detection system performs better than a direct detection system. Moreover, through results it is inferred that severe fading and misalignment losses result in poor error performance of the considered system errors on the performance of the considered cooperative system.

scholarly journals Unified Performance Analysis of MIMO Mixed RF/FSO Relaying System

2021 ◽  
Vol 11 (7) ◽  
pp. 3054
Author(s):  
Haodong Liang ◽  
Yiming Li ◽  
Maoke Miao ◽  
Chao Gao ◽  
Xiaofeng Li
Keyword(s):  
Outage Probability ◽  
Multiple Input Multiple Output ◽  
Approximate Expression ◽  
Ergodic Capacity ◽  
Free Space Optical ◽  
Decode And Forward ◽  
Pointing Error ◽  
Input Multiple Output ◽  
Practical Engineering ◽  
Relaying System

This paper investigates the asymmetric dual–hop multiple input multiple output (MIMO) mixed radio frequency (RF)/free space optical (FSO) decode–and–forward (DF) relaying system. This kind of system can utilize two different fading characteristic channels to reduce the possibility of the system falling into deep fading. In addition, each link of the system adopts MIMO technology to mitigate the disadvantages of fading. In this paper, the closed form expressions of the outage probability, bit error rate (BER) and average ergodic capacity are derived. The approximate expression of the system outage probability considering the pointing error is also derived. Additionally, asymptotic performance for diversity order and diversity–multiplexing tradeoff (DMT) of the system is analyzed and discussed, which provides direct theoretical basis for practical engineering design.

scholarly journals Gallager Exponent Analysis of Coherent MIMO FSO Systems over Gamma-Gamma Turbulence Channels

Entropy ◽  
2020 ◽  
Vol 22 (11) ◽  
pp. 1245
Author(s):  
Maoke Miao ◽  
Xiaofeng Li
Keyword(s):  
Fading Channels ◽  
Upper Bound ◽  
Communication Systems ◽  
Large Scale ◽  
Mimo Systems ◽  
Multiple Input Multiple Output ◽  
Block Code ◽  
Ergodic Capacity ◽  
High Signal ◽  
Free Space Optical

This paper studies the Gallager’s exponent for coherent multiple-input multiple-output (MIMO) free space optical (FSO) communication systems over gamma–gamma turbulence channels. We assume that the perfect channel state information (CSI) is known at the receiver, while the transmitter has no CSI and equal power is allocated to all of the transmit apertures. Through the use of Hadamard inequality, the upper bound of the random coding exponent, the ergodic capacity and the expurgated exponent are derived over gamma–gamma fading channels. In the high signal-to-noise ratio (SNR) regime, simpler closed-form upper bound expressions are presented to obtain further insights into the effects of the system parameters. In particular, we found that the effects of small and large-scale fading are decoupled for the ergodic capacity upper bound in the high SNR regime. Finally, a detailed analysis of Gallager’s exponents for space-time block code (STBC) MIMO systems is discussed. Monte Carlo simulation results are provided to verify the tightness of the proposed bounds.

Comparison of Aperture Averaging and Receiver Diversity Techniques for Free Space Optical Links in Presence of Turbulence and Various Weather Conditions

2014 ◽  
Vol 35 (4) ◽  
Author(s):  
Prabhmandeep Kaur ◽  
Virander Kumar Jain ◽  
Subrat Kar
Keyword(s):  
Outage Probability ◽  
Free Space ◽  
Direct Detection ◽  
Weather Conditions ◽  
Free Space Optical ◽  
Aperture Diameter ◽  
Receiver Diversity ◽  
Optical Links ◽  
Diversity Techniques ◽  
Aperture Averaging

AbstractIn this paper, we investigate the performance of a Free Space Optic (FSO) link considering the impairments caused by the presence of various weather conditions such as very clear air, drizzle, haze, fog, etc., and turbulence in the atmosphere. Analytic expression for the outage probability is derived using the gamma-gamma distribution for turbulence and accounting the effect of weather conditions using the Beer-Lambert's law. The effect of receiver diversity schemes using aperture averaging and array receivers on the outage probability is studied and compared. As the aperture diameter is increased, the outage probability decreases irrespective of the turbulence strength (weak, moderate and strong) and weather conditions. Similar effects are observed when the number of direct detection receivers in the array are increased. However, it is seen that as the desired level of performance in terms of the outage probability decreases, array receiver becomes the preferred choice as compared to the receiver with aperture averaging.

scholarly journals Impact of CCI on Performance Analysis of Downlink Satellite-Terrestrial Systems: Outage Probability and Ergodic Capacity Perspective

2021 ◽  
Author(s):  
Nhat-Tien Nguyen ◽  
Hong-Nhu Nguyen ◽  
Anh-Tu Le ◽  
Nhan Duc Nguyen ◽  
Dinh-Thuan Do ◽  
...  
Keyword(s):  
Outage Probability ◽  
Closed Form ◽  
Interference Cancellation ◽  
Signal To Noise Ratio ◽  
Satellite Communications ◽  
Ergodic Capacity ◽  
Power Coefficient ◽  
Imperfect Csi ◽  
Power Domain ◽  
Shadowing Effect

Abstract The evolution of non-orthogonal multiple access (NOMA) has raised many opportunities for massive connectivity with less latency in signal transmissions at great distances. Power-Domain NOMA transmits user signals superimposed in the same resource block by varying the power coefficient of each user according to their channel state information (CSI). At the receiver’s end, successive interference cancellation (SIC) is performed to extract the desired signal from the superimposed signal. Imperfect CSI should therefore be studied in this context. Satellite-terrestrial networks and relay networks have already gained significance in the field of communications through their efficient data transmission techniques. We aimed to integrate NOMA with a satellite communications network under both imperfect CSI and co-channel interference (CCI) from nearby systems with respect to analysis of ground user performance. In our considered system, two users perform downlink communications under Power-Domain NOMA. We analyzed the performance of this system with two modes of shadowing effect: Heavy Shadowing (HS) and Average Shadowing (AS). Performance was analyzed in terms of the outage probability and ergodic capacity of the system. We derived closed-form expressions and performed a numerical analysis. We discovered that the performance of two destinations depends on the strength of the transmit power at the satellite. However, floor outage occurs because the system depends on other parameters, such as satellite link modes, noise levels, and the number of interference sources. More specifically, if, for example, the number of interference sources is 5, the outage performance of the system experiences a decrease of approximately 40% at a signal to noise ratio (SNR) of 30 dB at the satellite. Outage probability and ergodic capacity became saturated at SNRs of 50 dB and 45 dB, respectively. To verify the authenticity of the derived closed-form expressions, we also performed Monte-Carlo simulations.

scholarly journals Partial Relay Selection for Two-Way Mixed RF/FSO DF Networks in the Presence of I/Q Imbalance

2021 ◽  
Author(s):  
Shweta Mittal ◽  
Pankaj Yadav ◽  
vivek dwivedi
Keyword(s):  
Outage Probability ◽  
Atmospheric Turbulence ◽  
Relay Selection ◽  
Research Work ◽  
Free Space Optical ◽  
Elementary Functions ◽  
Asymptotic Results ◽  
Decode And Forward ◽  
Partial Relay Selection ◽  
The Impact

Abstract In this paper, the study of mixed radio frequency (RF)/ free space optical (FSO) communication decode and forward (DF) two way relaying (TWR) has been presented. In fact, it has been considered that multiple relays are present out of which the best operational relay is selected as per the partial relay selection (PRS) methodology in the presence of outdated channel state information (CSI). Importantly, the relay nodes are assumed to operate in the presence of in phase (I) quadrature phase (Q) imbalance (IQI). The atmospheric turbulence on the FSO link has been modeled using the Malaga distribution with pointing errors. In addition to this, the impact of type of optical demodulation has been considered in the analysis. For the system model, outage probability expression has been derived in terms of Meijer-G and Fox’s H-functions. In addition to this, for the TWR system, the outage probability expressions have been modified to present asymptotic results in terms of elementary functions. The numerical analysis of the research work suggests that the overall mixed RF/FSO DF TWR system is impacted by the image rejection ratio (IRR) due to IQI, correlation between outdated CSI, atmospheric turbulence, pointing error and type of optical demodulation in addition to the amount of fading on the RF link.

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