This paper considers the application of mobile naked eye 3D display, which is represented by micro nano light-field control and super-surface optical technology, is likely to drive the development of mobile communication network by leaps and bounds. In view of the huge amount of data generated by holographic 3D display, this paper quantitatively analyzes the network data bandwidth and round-trip delay required by holographic 3D application, as well as the demand and future trend of other network bearing capacity indicators from several different perspectives, such as effective pixels and depth layer of naked eye 3D video; according to the 3GPP, the maximum peak data rate is given definition, find out a variety of factors that affect the carrying capacity of the post-5G network, and quantitatively give several specific indicators that can realize the naked eye 3D application, such as: the number of aggregation carriers, the number of numerologies, the order of massive multiple input multiple output, subcarrier spacing, etc., in order to obtain the safety margin of the network carrying capacity that can meet the future holographic 3D display application.
In order to reduce the blocking probability and improve energy efficiency in IP over flexible bandwidth optical networks, it is necessary to reduce the occupation of spectrum resources and the number of working network equipment when building the optical channels. Network equipment configuration with flexible line rates can improve the energy efficiency. Therefore, we propose an energy-efficient approach based on mixed-line-rate equipment configuration. To evaluate the performance of the proposed approach, we introduce a traditional energy-efficient approach with two line rates for comparison. The simulation results show that, compared with the traditional energy-efficient approach in IP over flexible bandwidth optical networks, our proposed energy-efficient approach can effectively reduce the blocking probability and network energy consumption by at least 20% with improved network performance.
Recently, Light-Emitting Diode (LED)-based Indoor Visible Light Communication (IVLC) technology is gradually becoming a research hot topic in the broadband communication access field. Currently,countries around the world are promoting the industrialization of 5G. One of the key requirements is that higher data transmission rates must be achieved. In order to further improve the transmission rate and system performance of IVLC system, it is necessary to introduce more advanced modulation and demodulation technologies. This paper first introduces the research background and system model of IVLC technology, and then summarizes the research progress of technologies such as Orthogonal Frequency Division Multiplexing (OFDM) modulation, Discrete Multi-Tone (DMT) modulation, Carrierless Amplitude-Phase (CAP) modulation and Multiple Input Multiple Output (MIMO) in IVLC. Finally, the future development trend and challenges of IVLC technologies are analyzed.
Acquisition speed and accuracy of satellite signal directly affect the working performance of software Global Positioning System (GPS) receiver. Aiming at the problem that the existing acquisition methods of satellite signals cannot achieve fast and accurate acquisition of GPS signals, the paper proposes a high-precision and fast acquisition method of GPS satellite signals based on blind separation. Firstly, the wavelet threshold algorithm is used to denoise the original signal of GPS satellite in order to improve the signal-to-noise ratio of satellite signal. Then the doppler effect frequency and phase of GPS satellite signal are solved by the proposed blind separation method based on subspace estimation algorithm to recover the unobserved source signals. Experimental results show that the proposed algorithm could accurately capture real satellite signals. Simulation results indicate that compared with the traditional algorithm, the acquisition algorithm in this paper is more suitable for the acquisition of weak signals, which shows that the algorithm has a better engineering application value.
Aiming at the problem of clock data recovery during the transportation of beyond 100 Gbit/s services using Flexible Optical Network (FlexO) technology, this paper designs and implements a new clock data recovery solution based on phase-locked loop frequency synthesizer to transform OTUCn to n OTU4 service data. Within a certain frequency offset of the OTU4 service frequency point, the customer clock is quickly recovered, and the retiming of the OTU4 service data is realized. Simulation and actual measurement prove that this solution can effectively meet the clock recovery requirements in FlexO. The client-side clock jitter of real-time recovery is less than 1×10-6, and it can ensure the continuous and stable transportation of OTU4 business data of multiple channels to the next stage.
Multi-view video is a three-dimensional technology that uses multiple cameras to shoot the same scene at the same time. Aiming at the problem of digital transformation required by the education industry, the article proposes a solution that combines multi-view video technology and Content Delivery Network (CDN)streaming media transmission technology. This solution is applied to distance learning and suitable for presenting the teaching process from multiple angles. The results show that in the face of distance education application scenarios, the combination of multi-view video technology and CDN can effectively solve the needs and challenges in teaching, which is the future development direction.
The interaction between light and nanostructures has always been one of the important topic in nanophotonics. The nanostructure of the core components play an important role in the function and performance of photonic devices. There are two approaches in the design of nanophotonic devices. One is based on physical principles and intuitive, while the other employs the idea of inverse design to obtain the optimal structure according to the required optical response. In recent years, inverse design has made great progress in nanophotonic devices. In particular, the technology of deep learning was recently introduced, promising for the design of high-performance nanophotonic devices. This article focuses on inverse design method of the nanophotonic devices. The background, key progress and typical applications of this emerging research direction are analyzed and summarized, and the challenges and prospect of inverse design are also presented.
In order to improve the gain flatness and transmission bandwidth of the fiber amplifier in the dense wavelength division multiplexing system, a theoretical model combining multi-wavelength pumping and cascade technology is established based on two non-same fiber types, when different wavelength combination modes are injected at different positions. Simultaneous pumping with multiple pumps can broaden the bandwidth, and flat gain fluctuations in fiber cascades. We use the fourth-order Runge-Kutta method to find the numerical solution of the N-channel Raman coupled wave equation. The Fourier curve with high fitting degree is used to fit the simulated spectral lines. Therefore, the Fiber Raman Amplifier (FRA) can be amplified first and then compensated. The transmission bandwidth and average gain value of the signal light are improved, and ideal gain flatness can be maintained without using a gain equalizer. The simulation results show that the final amplifier has an average gain of 36.75 dB, a transmission bandwidth of 57 nm, and a gain flatness of only 0.03 dB, which can provide a theoretical reference for the actual FRA design.
In this paper, the wavelength and the output power of the 3×3 channel micro-ring resonator under the non-linear function are studied and analyzed in the study of the theory model of the micro-ring-based optical communication device, and the influence of the nonlinear optical effect is not taken into account. The coupling theory formula of the micro-ring is derived, and the change of the permeability ratio of the micro-ring with the output light intensity is given. In this paper, the relationship between the through-through ratio and the wavelength of the micro-ring is constructed by simulation. The simulation results show that the effect of the phosphating solution on the non-linear effect of silicon nitride is more obvious and the string is more obvious. The disturbance is also large. The result of the final analysis is that the best working wavelength of the micro-ring of the silicon nitride material is in the vicinity of 0.7 μm, and the optimum working wavelength of the micro-ring for the phosphating material is 1.4 μm.
In order to achieve a compact structure to realize the refractive index sensor with high Figure of Merit (FOM) in a nanometer scale, a Metal-Dielectric-Metal (MDM) waveguide containing a metallic baffle side-coupled to U-shaped resonator is proposed to produce sharp and asymmetric Fano resonance. The asymmetric response line-shape of the Fano resonance is formed by the destructive interference between the wide continuous state generated by the single metallic baffle and the narrow discrete state excited by U-shaped resonator. The transmission properties of the proposed structure are numerically calculated by the finite element method, and the influence of structural parameters on the transmission spectrum and the value of FOM are analyzed quantitatively. The simulation results after parameter sweeping reveal that the FOM value of the optimized structure can attain to 47 382 and the sensitivity of resonant wavelength with refractive index drift is 800 nm/RIU. The waveguide structure can provide effective references for the design of nano-scale refractive index sensor.
In this paper, an ultra-small silicon optical multi-wavelength router is designed, which can realize the multi-wavelength routing function in optical communication window. The guided wave characteristics and the energy propagation characteristics of the light field are numerically simulated by using the Plane Wave Expansion (PWE) method and the Finite Difference Time Domain (FDTD) method, respectively. The designed wavelength router has the characteristics of high transmission efficiency, ultra-small overall size (total length about 20 μm), which can realize the routing function of 1.31, 1.55 and 1.65 μm optical wavelength at the same time.
To solve the problem that the traditional leaky wave antenna can only radiate linearly polarized waves, a new type of circularly polarized leaky wave antenna is proposed. The plasma waveguide is composed of uniform metal strips. The corrugated circular patches are loaded on either side of the Spoof Surface Plasmons (SSP) waveguide periodically and asymmetrically, and the scanning angle of the antenna beam can be effectively broadened. Besides, circular polarization performance is obtained by introducing perturbation on the radiating elements. The simulated results show that the antenna exhibits an impedance bandwidth of 43.5% (<-10 dB) and a 3 dB axial-ratio bandwidth of 31.3%. The impedance bandwidth of the beam steers is varied from 120 to 70 ° as frequency varies from 4.5 to 7.0 GHz. The antenna maximum gain is 12.48 dB in the whole band. Featured with a simple structure, easy fabrication and stable performance, the leaky wave antenna can be applied in wireless communication and sensor systems.
Under the multi-user and high-rate requirements of the current 5th-Generation system, in order to improve the performance of the system, an allocation algorithm based on the reward and punishment mechanism is proposed to achieve an efficient and high-throughput Physical Downlink Control Channel (PDCCH). The algorithm first considers the resource allocation of common search space and user equipment-special search space users. Then it introduces the reward and punishment mechanism when generating the user priority list to improve the blocking performance, system throughput of the cell edge users and the user fairness. Then the Radio Network Temporary Identity (RNTI) table allocation is simplified to control the resource allocation. Simulation results have shown that the improved algorithm reduces the blocking probability and allocation delay while ensuring that the resource utilization rate does not decrease. The algorithm has good reference value for practical engineering applications.
In massive Multiple-Input-Multiple-Output (MIMO) system, traditional detection algorithms suffer from more performance loss and higher complexity with increase in the number of antennas. In order to solve the complexity problem, a likelihood criterion based on neighborhood search as a branch strategy is proposed. Firstly, the quadratic programing model is constructed ,and the model is used to search tree as the root. Then, the node with the smallest value of the objective function is found as the branching node. Finally, the likelihood criterion is applied to the branching nodes for reducing the complexity of the branch. Specially, when the bit error rate achieves 10-4, the performance gain of the proposed algorithm is increased by 1.5 dB and the complexity of the proposed algorithm is reduced by about 69.84 percentage points compared with the traditional search tree algorithm in 16 quadrature amplitude modulation. The simulation results show that the proposed algorithm has better error performance and lower complexity.
In view of the fact that Fractional Fourier Transform (FRFT) has large computational complexities when the Chirp signals are detected blindly. This paper proposes a blind detection method for Chirp signal parameter estimation. Firstly, the Chirp signal is roughly estimated by window-length changing phase difference method and the least square method is used to fit and obtain the rough estimation value of the Chirp signal frequency modulation slope. Then, the Chirp signal is precisely estimated by FRFT, and the order of FRFT is obtained by Bisection method, which further reduces the computational complexity of the algorithm. The simulation result shows that the method of detecting the Chirp signal by using the modified window-length changing phase difference method and the FRFT at low Signal to Noise Ratio (SNR) has higher precision estimation value, and its normalization mean square error is close to Cramer-Rao lower bound. The method compared with FRFT exhaustive detection greatly reduces the computational complexity and has good engineering application significance.