Hybrid Rayleigh and Double-Weibull over impaired RF/FSO system with outdated CSI

In this paper, we propose a dual-hop radiofrequency (RF)/free-space optical system with multiple relays employing the decode-and-forward and amplify-and-forward with a fixed gain relaying scheme. The RF channels are subject to a Rayleigh distribution while the optical links experience a unified fading model emcopassing the atmospheric turbulence that follows the Málaga distribution (or also called the M -distribution), the atmospheric path loss, and the pointing error. Partial relay selection with outdated channel state information is proposed to select the candidate relay to forward the signal to the destination. At the reception, the detection of the signal can be achieved following either heterodyne or intensity modulation and direct detection. Many previous attempts neglected the impact of the hardware impairments and assumed ideal hardware. This assumption makes sense for low data rate systems but it would no longer be valid for high data rate systems. In this paper, we propose a general model of hardware impairment to get insight into quantifying its effects on the system performance. We will demonstrate that the hardware impairments have small impact on the system performance for low signal-to-noise ratio (SNR), but it can be destructive at high SNR values. Furthermore, analytical expressions and upper bounds are derived for the outage probability and ergodic capacity while the symbol error probability is obtained through the numerical integration method. Capitalizing on these metrics, we also derive the high SNR asymptotes to get valuable insight into the system gains, such as the diversity and the coding gains. Finally, analytical and numerical results are presented and validated by the Monte Carlo simulation.

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“…After applying the following identities [54, eqs. (8.4.2.5) and (2.24.1)] and using (15), the term J is finally derived as given by (51).…”

Section: Discussionmentioning

confidence: 99%

Aggregate Hardware Impairments Over Mixed RF/FSO Relaying Systems With Outdated CSI

Balti

Guizani

Hamdaoui

et al. 2018

IEEE Trans. Commun.

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“…where = 16(gβ+ ) 2 ψ i μ 2 α 2 β 2 κ 2 (g+ ) 2 γ th (1−ρ)μ1 . Next, after substituting (26) into (24), integral 2 is found as (…”

Section: Resultsmentioning

confidence: 99%

Exact Outage Probability Analysis of the Mixed RF/FSO System With Variable-Gain Relays

Petkovic

Trpovski

2018

IEEE Photonics J.

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This paper presents a unified analysis of the mixed radio-frequency (RF)/freespace optics (FSO) relaying system, with multiple variable-gain amplify-and-forward relays. The partial relay selection (PRS) is employed to select the active relay for further retransmission. Due to fast fading statistics of the first RF hop, it is assumed that the channel state information of the RF link is outdated, which is used for both the relay gain adjustment and the PRS procedure. The RF hops are subject to the Rayleigh fading, while the FSO hop is affected by the atmospheric turbulence and the pointing errors. The intensity fluctuations of the optical signal caused by atmospheric turbulence are modeled by the general Málaga (M) distribution, which takes into account the effect of multiple scattered components. An exact expression for the outage probability is derived. In addition, high-signal-to-noise-ratio approximations are provided, which can be used to efficiently determine the outage probability floor. Numerical results are validated by Monte Carlo simulations, which are used to examine the effects of the system and channel parameters on the RF/FSO system performance.

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“…Furthermore, we studied the impacts of the interference density, the blockage density, and the NLOS pathloss exponent on the rate coverage, and we show that the performance is significantly vulnerable to the severety of these factors. 29 APPENDIX A PROOF OF THE ACHIEVABLE RATE OF THE CELLULAR SYSTEM (13) After introducing the pdf expression of the effective SINR in (12), the achievable rate has the following generic integral form…”

Section: Discussionmentioning

confidence: 99%

“…The majority of the research attempts investigated mixed RF/FSO system considering various relaying schemes. The most prominent ones are Amplify-and-Forward (AF) [11]- [13], Decode-and-Forward (DF) [14], Quantize-and-Encode (QE) [15], and Quantize-and-Forward (QF) [16]. Moreover, many research attempts have assumed systems employing either single or multiple relays.…”

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Tractable Approach to MmWaves Cellular Analysis With FSO Backhauling Under Feedback Delay and Hardware Limitations

Balti

Johnson

2020

IEEE Trans. Wireless Commun.

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In this work, we investigate the performance of a millimeter waves (mmWaves) cellular system with free space optical (FSO) backhauling. MmWave channels are subject to Nakagami-m fading while the optical links experience the Double Generalized Gamma including atmospheric turbulence, path loss and the misalignment between the transmitter and the receiver aperture (also known as the pointing errors). The FSO model also takes into account the receiver detection technique which could be either heterodyne or intensity modulation and direct detection (IM/DD). Each user equipment (UE) has to be associated to one serving base station (BS) based on the received signal strength (RSS) or Channel State Information (CSI). We assume partial relay selection (PRS) with CSI based on mmWaves channels to select the BS associated with the highest received CSI. Each serving BS decodes the received signal for denoising, converts it into modulated FSO signal, and then forwards it to the data center. Thereby, each BS can be viewed as a decode-and-forward (DF) relay. In practice, the relay hardware suffers from nonlinear high power amplification (HPA) impairments which, substantially degrade the system performance. In this work, we will discuss the impacts of three common HPA impairments named respectively, soft envelope limiter (SEL), traveling wave tube amplifier (TWTA), and solid state power amplifier (SSPA). Novel closed-forms and tight upper bounds of the outage probability, the probability of error, and the achievable rate are derived. Capitalizing on these performance, we derive the high SNR asymptotes to get engineering insights into the system gain such as the diversity order. I. INTRODUCTIONWith the rapid increase of the internet base, the mobile stations, and the extremely high demand for bandwidth, the microwave Radio Frequency (RF) cellular systems have reached a saturation level owing to the limited spectrum, and expensive access licence. Although, many research attempts in cognitive radio allow parallel utilization of the bandwidth between the primary and secondary users, the last ones still suffer from the spectrum drought since they are always leveraging from some spectrum holes left by the primary users. Moreover, the backhaul network cannot support the big data flow even for the licenced primary ones.Moreover, the backhaul network cannot support the big data flow even for the licenced primary ones. Recent attempts have proposed the usage of optical fibers (OF) as a solution for the backhaul network congestion. However, for ultra dense cellular networks, a large number of OF are needed given that these cable installations are very costly and the space installation of such cables to serve large number of cells/users are limited and even restricted in some areas. A. MotivationTo support such network densification, millimeter waves (mmWaves) technology, which refers to the spectrum from 28 to 300 GHz, has emerged as a promising solution to replace microwave communications. In fact, mmWaves provide a large available spectrum...

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Hybrid Rayleigh and Double-Weibull over impaired RF/FSO system with outdated CSI

Cited by 21 publications

References 23 publications

Aggregate Hardware Impairments Over Mixed RF/FSO Relaying Systems With Outdated CSI

Aggregate Hardware Impairments Over Mixed RF/FSO Relaying Systems With Outdated CSI

Exact Outage Probability Analysis of the Mixed RF/FSO System With Variable-Gain Relays

Tractable Approach to MmWaves Cellular Analysis With FSO Backhauling Under Feedback Delay and Hardware Limitations

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