Vortex beam carrying orbital angular momentum (OAM) is disturbed by oceanic turbulence (OT) when propagating in underwater wireless optical communication (UWOC) system. Adaptive optics (AO) a powerful technique used to compensate for distortion and improve the performance of UWOC In this work, we propose diffractive deep neural network (DDNN) based AO scheme caused OT, where DDNN trained obtain mapping between intensity distribution vortex its corresponding phase screen representing OT....

Abstract In this paper, we present an effective way for simulating oceanic turbulence channel on the beam carrying orbital angular momentum (OAM). The influence caused by phase and intensity of propagation is equivalent to that passing through several individual screens generated power spectrum inversion method at regular intervals. A modified subharmonic compensation then further balance screen losses lower frequency components in method. feasibility verified theoretical structure function...

Among many others, LoRa/LoRaWAN is one of the most widely employed technologies to support Internet Things applications for low-power and long-range wireless devices. LoRaWAN a medium access control (MAC) layer protocol based on traditional Aloha algorithm which reveals great degraded throughput when large number devices attempt communicate over shared channel at same time. Aiming this scalability issue, we propose introduce distributed queueing (DQ) into MAC LoRa physical layer, named...

Reconfigurable intelligent surface (RIS) is an attractive solution to smart radio environment, which has a promising potential mitigate Doppler effect for mobile channels. In this letter, we present mitigation method assisted by RIS high-speed scenarios, including the design of transmission protocol and phase control pattern. The enhanced version two-stage protocol. A two-phase training sequence introduced in first stage, decouple estimates direct cascaded channels simplify matrix LS...

In the paper, we experimentally demonstrate propagation property of Laguerre-Gaussian (LG) beams carrying fractional orbital angular momentum (FOAM) in an underwater environment. The effects topological charge (TC), temperature gradient, and salinity on transmission LG-FOAM beam turbulence are analyzed, optimum interval TC for FOAM communication their help improvement system capacity discussed. results show that both gradient have serious impacts beam, meanwhile, plays a heavier influence....

Vortex beam carrying orbital angular momentum (OAM) suffers heavily interference from oceanic turbulence (OT) when it is transmitted through underwater wireless optical communication (UWOC) system. Adaptive optics (AO) up to now the best candidate improve UWOC communications quality. In this work, we propose a generative adversarial network (GAN) based AO scheme compensate for distortion caused by OT, where GAN first trained numerical simulations obtain mapping between intensity distribution...

Orbital angular momentum (OAM) has the characteristics of mutual orthogonality between modes, and been applied to underwater wireless optical communication (UWOC) systems increase channel capacity. In this work, we propose a diffractive deep neural network (DDNN) based OAM mode recognition scheme, where DDNN is trained capture features intensity distribution modes output corresponding azimuthal indices radial indices. The results show that proposed scheme can recognize accurately quickly....

Orbital angular momentum (OAM) has been widely used in underwater wireless optical communication (UWOC) systems due to the mutual orthogonality between modes. However, wavefront distortion caused by oceanic turbulence (OT) on OAM mode seriously affects its recognition and quality. In this work, we propose a hybrid opto-electronic deep neural network (HOEDNN) based scheme. The HOEDNN model consists of diffractive DNN (DDNN) convolutional (CNN), where DDNN is trained obtain mapping intensity...

Ferromagnetic resonance (FMR) measurement was performed at the frequency of 9.8 GHz and room temperature on a series Fe-SiO2 granular films fabricated by Ar+-beam sputtering technique. Our results indicated that when iron volume fraction (fv) exceeds 0.28, FMR spectra are superpositions modes surface modes. The analysis effective anisotropy field suggests intrinsic (including interface one) becomes maximal fv near percolation threshold (fp). In particular, it found for with fv=0.42 spin wave...

Internet of Remote Things (IoRT) networks utilize the backhaul links between unmanned aerial vehicles (UAVs) and low-earth-orbit (LEO) satellites to transfer massive data collected by sensors. However, change rapidly due fast movement both UAVs satellites, which is different from conventional wireless networks. Additionally, various requirements IoRT multiservices, system performance should be comprehensively considered. Thus, an adjustable link selection algorithm for a LEO-UAV-sensor-based...

Satellite-based networks have emerged as a promising solution for global Internet-of-Things (IoT) to bridge the coverage gaps of terrestrial (TNs). However, due wider and rapid movement, satellite-based communication has two distinct characteristics from one, notably longer propagation delay larger Doppler shift. These distinctions pose significant technical challenges implementing efficient random access (RA) schemes in networks. In this letter, we propose an RA scheme tailored satellite...

Abstract Satellite communication, especially low earth orbit satellites, an important part of the space‐air‐ground integrated network, is a promising solution to support global coverage and reliable communication. However, originally connected links will be off, when satellites move into polar regions. In addition, condition path broken dramatically increase with number increasing. Thus, it continually considerable challenge design efficient stationary routing algorithm for intra‐satellites....

Self-interference (SI) channel characteristics are crucial for SI cancellation (SIC) techniques of in-band full-duplex (IBFD) wireless communications. This paper develops two geometry-based statistical models-geometry-based concentric ellipses model (GBCEM) and circles (GBCCM)-for systems in micro- macrocell environments, respectively, to analyze the reflected-path (RSI) compared with desired signal (DS). The probability density functions incident angle path length derived identify fading...

Abstract LoRa, due to its advantage of long-range communication capability, is promising for Internet Things (IoT) and space-air-ground communications. However, the conventional MAC protocol used with LoRa classified as an Aloha-based algorithm, which leads drastic decrease in throughput when a huge amount end-devices try access network. To achieve stable high we propose design combine distributed queueing (DQ) in-band-full-duplex (IBFD) technologies. The usage DQ mechanism benefit fast...

A P2P-SIP architecture relying on open-source SIP stacks and JXTA platform is proposed, where the centralized registration location are implemented via P2P publishing service location, respectively. novel protocol-JXP presented a prototype designed developed based LINUX. The system has been for transporting typical VoIP call controls real-time media stream.

IEEE 1588 specifies the precision time protocol (PTP) to synchronize independent locks with high synchronization accuracy. In this paper, PTP is implemented based on embedded FPGA board hardware timestamp and performances of system setup for wire wireless network are presented analyzed.