Mixed RF/FSO Cooperative Relaying Systems With Co-Channel Interference

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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“…where γ z is the average SNR of a single interferer. The joint pdf of the outdated and updated SNRs is given by [31,Eq. (8)]…”

Section: Channel Modelmentioning

confidence: 99%

“…where I ν (·) is the ν-th order modified Bessel function of the first kind and γ is the average SNR. Assuming that the UE selects the BS of rank k conditioned on the correlation factor ρ and refering to [31,Eq. (28)], the pdf of the effective SINR γ eff can be expressed as…”

Section: Channel Modelmentioning

confidence: 99%

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 (4) and (5), the average SNR γ X = P s F 2 N 0 for the satellite link between satellite S and node X, X ∈ {R, E} is related to parameter F, which denotes a scaling parameter including the effects of free space path loss, antenna pattern, etc. [21].…”

Section: Satellite Communicationsmentioning

confidence: 99%

“…Substituting (5) and (15) into (16), the ASC C DF s with the the relay node working under DF protocol or variable-gain AF protocol can be expressed as…”

Section: Decode-and-forward Cooperative Relayingmentioning

confidence: 99%

Physical Layer Security of Hybrid Satellite-FSO Cooperative Systems

Mathur

Cheffena

et al. 2019

IEEE Photonics J.

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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 decodeand-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.

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“…The interfering signals have been modeled using the Nakagami-m fading distribution, while the FSO systems are assumed to follow doublegeneralized Gamma (D-GG) turbulence model to demonstrate exact and asymptotic performance of the overall system in [4]. Moreover, the effect of multiple CCIs on the mixed RF/FSO OWR systems have been analyzed in [5] where the authors have derived expressions of the OP, BER and capacity for channel state information (CSI) assisted system. On the other hand, impact of multiuser diversity (MUD) on interference limited mixed RF/FSO OWR systems has been indicated by the authors of [6].…”

Section: Introductionmentioning

confidence: 99%

Interference-Limited Mixed MUD-RF/FSO Two-Way Cooperative Networks Over Double Generalized Gamma Turbulence Channels

2019

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In this letter, the performance of multiuser-radio frequency/free space optics (RF/FSO) two-way relay network in the presence of interference is investigated. The FSO link accounts for pointing errors and both types of detection techniques, i.e. intensity modulation/direct detection as well as coherent demodulation, which is modeled as double generalized gamma (D-GG) turbulence channel. On the other hand, the multiple users on the RF link are assumed to undergo Nakagami-m fading. Multiple co-channel interferers (CCIs) which corrupt the signal at relay node are modeled using Nakagami-m distribution. Specifically, the exact closed-form expressions for the outage probability (OP) of the overall system is derived. Moreover, the closed form expression for the achievable sum-rate (ASR) of the considered system is presented. In order to simplify the results, the asymptotic approximations of the OP and ASR are derived in terms of elementary functions. The results presented in the paper are validated by Monte-Carlo simulations.

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Mixed RF/FSO Cooperative Relaying Systems With Co-Channel Interference

Cited by 82 publications

References 58 publications

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

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

Physical Layer Security of Hybrid Satellite-FSO Cooperative Systems

Interference-Limited Mixed MUD-RF/FSO Two-Way Cooperative Networks Over Double Generalized Gamma Turbulence Channels

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