Unmanned aerial vehicles (UAVs) can be harnessed as relay nodes in free-space optical (FSO) communication systems to realize a flexible and cost-effective approach for delivering on-demand next-generation wireless communications. However, fading channels adversely affect the performance of UAV-assisted dual-hop FSO owing various factors. This paper presents unified system analysis FSO/FSO with amplify-and-forward relaying protocol intensity modulation/direct detection technique. For general...

The integration of free-space optical (FSO) communications and relay technology has been envisioned as a promising effective solution to achieve substantial performance gains for future deep space systems. In this article, the system dual-hop FSO/FSO framework is studied, best our knowledge, first time, in presence plasma absorption, coronal turbulence, pointing error impairments. More specifically, Málaga fading distribution model employed characterize channel, since it large scope...

A reliable deep space communications system plays a key role in extending the range of and has become an indispensable part information networks. With emergence many exploration projects, it can be envisioned that new era research on arrived. However, performance is severely degraded by solar scintillation, which occurs frequently during superior conjunction. In this article, we first review state art scintillation research, including definition influencing factors, assessment methods,...

Mixed radio frequency (RF) and free space optical (FSO) communications are a promising alternative technology for backbone networks of next-generation wireless communications, but bottlenecks exist due to atmospheric turbulence. In this paper, the performance amplified-and-forward dual-hop mixed RF/FSO systems with heterodyne detection intensity modulation/direct techniques, in consideration pointing errors, is investigated. particular, an asymmetric fading environment considered where RF...

The Internet of Vehicles (IoV), as a development and complement the Thing, has attracted extensive attention is expected to play crucial role in human society with matured space-air-ground integrated networks (SAGIN). Here, we devote ourselves establish investigate unmanned aerial vehicle (UAV)-assisted radio-frequency (RF)/free space optical (FSO) communication system under amplified-and-forward protocol variable gain. More specifically, assume RF link follows <inline-formula...

The influence of oceanic turbulence and pointing error impairments on the underwater wireless optical communication (UWOC) systems is considered in this study. We propose a generalized fading model, which comprises path loss due to absorption scattering, (modeled by Málaga distribution), resulting from ocean movements. Thereafter, closed-form expressions average symbol probability (SEP) channel capacity are proposed for waves propagate with M-ary pulse position modulation (PPM) under...

Opportunistic networks aim to provide reliable communications in an intermittently connected environment. The research cache management of opportunistic has been done a lot those aspects, such as queue strategy, replace, redundancy delete, etc. But most the existing studies only focus on subdivision buffer management. To deal with case, this article proposes comprehensive integration called comprehensive-integrated (CIM), which takes all information relevant message delivery and network...

In view of the defects that low data transmission rate and high range sidelobes in radar communication integrated systems based on traditional orthogonal frequency division multiplexing (OFDM), an OFDM waveform structure associated processing technique is proposed. Firstly, a phase-coded (PC-OFDM) cyclic shifts m-sequence given, where corresponding time shift controlled by data. Then, discrete Fourier transform (DFT) correlation analyzed detail. Theoretical analysis simulation results show...

The influence of the ocean depth and anisotropic tilt angle on vertical underwater wireless optical communication (UWOC) systems is considered in this study. We propose a power spectrum model oceanic turbulence with an for first time. Thereafter, expression scintillation index derived spherical wave propagating over link. In addition, considering temperature salinity, relevant data Atlantic Pacific oceans at different depths are selected to study further effect index. results indicate that...

This letter proposes a reconfigurable intelligent surface (RIS)-assisted stochastic unmanned aerial vehicle (UAV) millimeter wave relay communication system. Regarding characteristics of distance in UAV links, inherent identities the path loss, as well molecular absorption impacts, probability density function and cumulative distribution proposed system are formulated with help moment matching estimation method. Based on this, we determine metric expressions outage (OP), average bit error...

Energy saving is critical for the cloud radio access networks (C-RANs), which are composed by massive units (RAUs) and energy-intensive computing (CUs) that host numerous virtual machines (VMs). We attempt to minimize energy consumption of C-RANs, leveraging RAU sleep scheduling VM consolidation strategies. formulate problem in C-RANs as a joint resource provisioning (JRP) RAUs CUs. Since active selection coupled with consolidation, JRP shares some similarities special bin-packing problem....

Computational resource allocation is a critical issue for the baseband unit (BBU) pool in cloud radio access network (C-RAN). There are multiple resources BBU, including CPU, memory, disk, etc. The virtual machines (VMs) have diverse requirements along these to handle signal processing of corresponding remote units (RRUs). Consolidating VMs BBUs based on single incurs over-allocation that not explicitly allocated. Therefore, we study multi-resource problem CRANs, which aims minimize number...

Due to its suitability combine the radar and communication (RadCom) applications simultaneously, integrated RadCom systems using orthogonal frequency division multiplexing (OFDM) signals have been widely investigated. However, Doppler processing strategy in traditional OFDM radars exhibits low accuracy along with high complexity caused by data bits conveyed on chirps. In this letter, we propose a method for phase-coded OFDM-based system. The system can also be reduced adopting sampling rate,...

Optical communication has a great potential for the future deep space communication, while amplitude fluctuations caused by coronal solar wind irregularities been challenging topic during superior conjunction. In this paper, closed-form expression optical waves propagation through non-Kolmogorov turbulence is derived establishing generalized spectrum model. The profound impact of parameters on bit error rate (BER) performance free system also investigated based allows easy analysis evolution...

The properties of terahertz waves propagation in a homogeneous, magnetized, and collisional plasma are studied this paper. We first theoretically calculate the reflectance absorbance coefficients for passing through region. Then, numerous simulations conducted to investigate influence on propagation. According results, density, collision frequency, magnetic field play important roles dielectric spectra, then result large impacts with variation thickness, incident angle, gas pressure....

Free space optical (FSO) communication has recently aroused great interest in academia due to its unique features, such as large transmission band, high data rates, and strong anti-electromagnetic interference. With the aim of evaluating performance an FSO system extending line-of-sight distance, we propose unmanned aerial vehicle (UAV)-assisted dual-hop equipped with amplify-and-forward protocol at relay node. Specifically, consider impairments atmospheric absorption, pointing errors,...

Deep-space optical communication has garnered increasing attention for its high data transfer rate, wide bandwidth, and transmission speed. However, coronal plasma turbulence severely degrades signals during superior solar conjunction. In this study, we introduce the models density generalized non-Kolmogorov power spectrum. Based on these models, derive variance of phase fluctuations with assistance Rytov theory in weak regime involving various variables, such as outer scale, spectral index,...

The benefits of higher data transmission rates, extensive communication frequency bandwidths, reduced power consumption, and enhanced anti-interference capabilities make inter-satellite optical (ISOC) a promising technology for the future. However, during orbital motion, satellites are subjected to external perturbation forces, which affect performance ISOC system. This paper establishes an system consisting two co-orbital orbiting Earth under influence perturbations. For what we believe be...

Solar scintillation refers to the rapid amplitude fluctuations of radio signal passing through large-scale coronal irregularities. In this letter, index model is first derived characterize wave propagation in turbulence during superior solar conjunction. The proposed takes into account non-Kolmogorov with Rytov approximation method. After that, bit error rate (BER) performance analyzed based on model, which has instructional significance for deep space communication but still remains largely...

The influence of anisotropic weak-to-strong oceanic turbulence on the performance underwater optical communication (UWOC) systems is investigated in this paper. Málaga distribution fading model used to statistical a spherical wave propagating through turbulence, which versatile turbulence. First, scintillation index for formulated, and closed-form expressions outage probability average channel capacity UWOC are then proposed terms Meijer's G function. simulation results demonstrate that both...