With rapid advances of solar blind ultraviolet LED and detecting technology in recent years, communication gradually becomes a research hotspot due to its inherent advantages: low background noise, non-line-of-sight(NLOS) good secrecy. The strong scattering characteristics atmospheric render waveband the ideal choice for achieving NLOS optical communication. This paper reviews history status both China abroad, especially introduces three main issues communication: channel model, system...

Monte-Carlo models are analyzed for multiple scattering channels in optical wireless communications. It is demonstrated that the system impulse response function can be obtained by integration model. The convergence performance model and improved introducing different sampling methods. simulation results show gamma channel only applied to cases where common volume between transmitted light beam receiving field-of-view open. Numerical suggests a three-order case, computation efficiency of...

Multi-beam low earth orbit (LEO) satellites are emerging as key components in beyond 5G and 6G to provide global coverage high data rate. To fully unleash the potential of LEO satellite communication, resource management plays a role. However, uneven distribution users, coupling multi-dimensional resources, complex inter-beam interference, time-varying network topologies all impose significant challenges on effective communication management. In this paper, we study joint optimization beam...

The full-duplex optical communications can be achieved simply by separating the transmitting link and receiving in space. However, it is challenging to achieve non-line-of-sight (NLOS) ultraviolet (UV) communication due serious self-interference caused strong multiple scattering effects of UV signals. To explore capacity NLOS communications, this paper, we first quantify using an analytical channel impulse response function. Based on quantified self-interference, then derive error rate...

Displacement based quantum receivers can beat the standard limit and have gained increasing attention in recent years. The displacement operation value be estimated calibrated by using Fock states as probes. In this Letter, we focus on impacts of thermal noise when preparing probes estimation performance. We first derive density matrix photon statistics noisy displaced number state with a uniformly distributed phase. Based derived matrix, then analyze performance estimating operations...

None-line-of-sight (NLOS) ultraviolet (UV) communication has attracted increasing attention in recent years. The atmospheric turbulence will deteriorate the performance of NLOS UV communications. Existing works on turbulent model single-scattering channels only considered narrow beam cases. In this letter, we propose a channel using equivalent scattering points (ESPs) approach to characterize fluctuation effect signals under large full-width divergence angles and field-of-view angles. An...

The study on short-range ultraviolet communication (UVC) channel modeling is often based prolate-spheroidal coordinate system in the previous studies. In this letter, we propose a single scattering coplanar model spherical system, where transmitter beam and receiver field of view (FOV) can point arbitrarily under limitation that sum transceiver elevation angles half their own FOV less than 180°, are above ground. We utilize number intersections between special ray cone conical surface to...

Spatial diversity receptions are usually employed to improve the performance of scattering based optical communication (SOC) systems. Existing works on for SOC systems ignored detecting properties photomultiplier tube (PMT) receivers. In this paper, we focus single-input multiple-output (SIMO) using PMT We first present system model SIMO considering link geometries and prove that traditional maximum-ratio combining is no longer optimal method Then propose statical derive its statistical...

The study on multiple scattering propagation of non-line-of-sight ultraviolet communication is based the stochastic Monte Carlo method in previous studies. In this letter, an integral model two-order and three-order deduced a narrow beam case. A prolate-spheroidal coordinates system isotropic hypothesis are used to simplify model. Compared with method, computational efficiency stability proposed much better do not decrease increase range. This letter provides new way obtain path loss long ranges.

The performance of Kennedy receiver with threshold detection is analyzed in the presence thermal noise. A lower bound first derived for error probability noise and it shown that greatly affected by Then we analyze using maximum a posteriori detection, which proven to be equivalent detection. We also optimize displacement operation improve further performance. Numerical results show can surpass standard quantum limit achieved homodyne when average number photons smaller than 0.1. optimized 0.2.

A free-space optical communication system using non-mode-selective photonic lantern (PL) based coherent receiver is studied. Based on the simulation of photon distribution, power distribution at single-mode fiber end PL quantitatively described as a truncated Gaussian over simplex. The signal-to-noise ratios (SNRs), bit-error rate (BER), and outage probability selection combining (SC), equal-gain (EGC), maximal-ratio (MRC) Gamma-Gamma turbulence channels are analyzed compared with (SMF)...

Spatial diversity techniques are usually used to mitigate the influence of turbulence in free-space optical communication (FSOC) with photon-counting receivers, especially when links weak. A maximum likelihood (ML) detection can be directly applied outputs receivers. However, it is challenging obtain an analytical error probability for ML detection. In this letter, we derive under both turbulent and non-turbulent cases by equivalently considering <inline-formula...

The single-scattering model for short-range ultraviolet (UV) communication is often replaced by an approximate due to its simplified calculation. However, there are certain errors associated with the existing models. To reduce errors, a spherical crown (SC) in narrow beam case derived this letter, where we assume that differential volume thin layer of SC. Meanwhile, applicable conditions and error range SC provided. calculation results indicate models from -1.4 6.0 dB while those -0.2 0.4...

Sensitivity to weather conditions is the principal limitation of free-space optical communication. However, for scattering based ultraviolet (UV) non-line-of-sight (NLOS) communication, atmospheric effect functions as an attenuation factor and potentially a performance enhancer. To investigate UV NLOS transmission coverage under different conditions, we employ Mie Theory in conjunction with classical aerosol hydrometeor particle models estimate absorption coefficient, phase function. We then...

Ultraviolet (UV) communication is a promising technology for civilian and military secure systems due to nonline-of-sight transmission, low background noise, high local security. The full-duplex relay-assisted UV communications can achieve longer distances higher efficiency of time–frequency utilization compared with direct communications. However, the strong scattering effect, serious interrelay-interference (IRI) inevitably introduced in multihop relay links. To mitigate impacts IRI, this...

An optical quantum communication system with receiver diversity is proposed for free-space using the combining technique and a generalized Kennedy receiver. The channel model of established P -representation in presence both turbulence thermal noise. A conditional dynamics based threshold detection to mitigate influence error probabilities different types receiver, i.e., Type-II are analytically studied lower bounds these obtained. Numerical results show that fail either or performance can...

The formation of various deep silicon structures by using plasma etching has wide applications in sensors, micro-electro-mechanical systems (MEMS) and 3D wafer level integration. However, the fabrication cavities with high accuracy depth within large size is still a challenge due to amount. Herein, cavity uniformity approaching 3% ~100 ?m on 12 inch achieved through tuning focus ring height, baffle shape, double zone helium cooling system chamber pressure. simulation electromagnetic field...

Continuous variable quantum key distribution (CV-QKD) protocol has drawn much attention due to its compatibility with existing optical communication systems. In this paper, we propose a quaternary modulated CV-QKD using displacement receivers and adopt the post-selection scheme overcome '3dB limit'. We first establish model of receiver for discriminating coherent signals in realistic situation. The performance non-adaptive multi-stage feedforward are both investigated under different noises...

Continuous variable quantum key distribution attracts increasing attention in recent years due to its potential high secret rates and the compatibility with existing communication infrastructure. This letter derives rate for a binary modulated continuous using an optimally displaced threshold detection post-selection. To improve rate, we optimize post selected area coherent amplitude different transmission efficiency of channel under thermal noises. Both individual collective beamsplitter...

Micro/nanostructures with high aspect ratios in silicon wafers obtained by plasma etching are of great significance device fabrication. In most cases, the scallop nanostructure deep should be suppressed. However, could applied electronic fabrication as characteristic information, which indicates balance between deposition and etching. this work, applications nanostructures process optimization environmental protection demonstrated. addition, minimum effect cycle time on size is reported for...

Because of the potential applications in quantum information processing tasks, discrimination binary coherent states using generalized Kennedy receiver with maximum a posteriori probability (MAP) detection has attracted increasing attentions recent years. In this paper, we analytically study performance having optimally displaced threshold (ODTD) realistic situation noises and imperfect devices. We first prove that MAP for is equivalent to situation. Then analyze properties optimum...

The strong scattering effects of ultraviolet (UV) signals in the atmosphere enables non-line-of-sight (NLOS) ability UV communications, but introduces large time dispersion channel impulse response (CIR), which inevitably results serious inter-symbol interferences (ISIs). Because a larger transmitting rate can introduce ISI, it is meaningful to study impact CIR on ISI and further quantify achievable information (AIR) NLOS communications. In this paper, we analyzed influence both coplanar...