Fifth-Generation Filmmakers Advance Towards the Market

POSSIBLY no other schoolreunion has aroused moreattention or had such apalpable ethos of com-merce than that of the BeijingFilm Institute class of 1978.

The Fifth-Generation FilmMakers

CHINA'Scollegeentranceexaminationsystemhadbeensuspendedduringthe"culturalrevolution"(1966-76)until1978.Oncecollegesre-opened,agroupofeducatedurbanyouthswhohadbeenworkinginthecountrysidewereadmittedtotheBeijingFilmAcademy.Afterfouryears'study,thenewgr...

A 24−30 GHz 8-element dual-polarized 5G FR2 phased-array transceiver IC with 20.8-dBm TX OP1dB and 4.1-dB RX NF in 65-nm CMOS

This article presents an 8-element dual-polarized phased-array transceiver(TRX)front-end IC for millimeter-wave(mm-Wave)5G new radio(NR).Power enhancement technologies for power amplifiers(PA)in mm-Wave 5G phased-array TRX are discussed.A four-stage wideband high-power class-AB PA with distributed-active-transformer(DAT)power combining and multi-stage second-harmonic traps is proposed,ensuring the mitigated amplitude-to-phase(AM-PM)distortions across wide carrier frequencies without degrading transmitting(TX)power,gain and efficiency.TX and receiving(RX)switching is achieved by a matching network co-designed on-chip T/R switch.In each TRX element,6-bit 360°phase shifting and 6-bit 31.5-dB gain tuning are respectively achieved by the digital-controlled vector-modulated phase shifter(VMPS)and differential attenuator(ATT).Fabricated in 65-nm bulk complementary metal oxide semiconductor(CMOS),the proposed TRX demonstrates the measured peak TX/RX gains of 25.5/21.3 dB,covering the 24−29.5 GHz band.The measured peak TX OP1dB and power-added efficiency(PAE)are 20.8 dBm and 21.1%,respectively.The measured minimum RX NF is 4.1 dB.The TRX achieves an output power of 11.0−12.4 dBm and error vector magnitude(EVM)of 5%with 400-MHz 5G NR FR2 OFDM 64-QAM signals across 24−29.5 GHz,covering 3GPP 5G NR FR2 operating bands of n257,n258,and n261.

基于5G+区块链的危重新生儿转运信息平台构建策略与效果评估

运用第五代移动通信技术(fifth generation,5G)的低延时、高速率特点和区块链技术的去中心化、不可纂改特点,构建危重新生儿转运信息系统,实现了医疗资源和医疗数据共享,保障转运间医疗服务连续性,加强转运途中的实时急救指导。复旦大学附属儿科医院建设了5G+区块链的危重新生儿转运信息平台,设计融合5G数据传输功能的新生儿转诊舱,建立了转出医院、医疗急救中心、接诊医院三位一体的危重新生儿急救转诊网络体系。所有危重新生儿转运中照护前移,实现了“上车即入院”,提升了危重新生儿转运质量。

Massive MIMO system lower bound spectral efficiency analysis with precoding and perfect CSI

The analytical lower bound of Spectral Efficiency(SE)of downlink transmission of the Massive Multiple Input Multiple Output(Ma-MIMO)system is analyzed.In this paper,we derive some novel and approximate mathematical expressions for the lower bound of the SE of a Ma-MIMO with linear precoding schemes,i.e.,Minimum Mean Square Error(MMSE)and Zero-Forcing(ZF).For simulation analysis of the SE,we consider three joint users and antenna scheduling algorithms,namely,the semi-orthogonal,random,and distance-based user scheduling algorithms,whereas the antennas are selected based on Maximum Signal to Noise Ratio(MSNR)with scheduled users.The channel between the user and the transmitter is assumed to have characteristics of Small Scale Fading(SSF)and Large Scale Fading(LSF)with the Rayleigh fading model.We investigate the effect of the variation of transmitting SNR,the number of base station antennas(M),and the radius(R)of the cell area on the SE.We simulate the downlink transmission of Ma-MIMO and compare the simulation and analytical results.It is observed that the trends of variation of both results are similar to the variation of identical factors,and the difference between the simulated and analytical lower bounds of the SE is approximately 1-1.5 bits.The analytical lower bound is smaller than the simulation result.

Ambient BackCom in beyond 5G NOMA networks: A multi-cell resource allocation framework

The research of Non-Orthogonal Multiple Access (NOMA) is extensively used to improve the capacity of networks beyond the fifth-generation. The recent merger of NOMA with ambient Backscatter Communication (BackCom), though opening new possibilities for massive connectivity, poses several challenges in dense wireless networks. One such challenge is the performance degradation of ambient BackCom in multi-cell NOMA networks under the effect of inter-cell interference. Driven by providing an efficient solution to the issue, this article proposes a new resource allocation framework that uses a duality theory approach. Specifically, the sum rate of the multi-cell network with backscatter tags and NOMA user equipment is maximized by formulating a joint optimization problem. To find the efficient base station transmit power and backscatter reflection coefficient in each cell, the original problem is first divided into two subproblems, and then the closed form solution is derived. A comparison with the Orthogonal Multiple Access (OMA) ambient BackCom and pure NOMA transmission has been provided. Simulation results of the proposed NOMA ambient BackCom indicate a significant improvement over the OMA ambient BackCom and pure NOMA in terms of sum-rate gains.

Research on Online Education Consumer Choice Behavior Path Based on Informatization

The application of information and communications technology(ICT)in the education industry is becoming more and more extensive,and online education realized through ICT is developing in full swing.The influence of ICT on online education consumer's choice behavior is the core issue of online education industry development research.The research on the interactive path and methods of information and online education consumer choice behavior is worth exploring and revealing.This study introduces the word-of-mouth factor as a new research variable under the framework of the Rational Choice Theory model(RCT)and the structural equation method to conduct empirical research and theoretical analysis to verify the validity of the hypothesis and model.The fifthGeneration mobile communication system(5 G)analyses the factors affecting online education consumer behavior choices based on the premise of ICT.Research on the path between ICT and choice behavior provides new ideas for online education consumer choice behavior research and ICT and content and provides a new scenario.This article is a cross-disciplinary research content in theory,and its innovation opens up a new path for the management of ICT research.The research results have innovative significance and value at both the theoretical and practical levels.

Deep learning based Doppler frequency offset estimation for 5G-NR downlink in HSR scenario

In the fifth-generation new radio(5G-NR) high-speed railway(HSR) downlink,a deep learning(DL) based Doppler frequency offset(DFO) estimation scheme is proposed by using the back propagation neural network(BPNN).The proposed method mainly includes pre-training,training,and estimation phases,where the pre-training and training belong to the off-line stage,and the estimation is the online stage.To reduce the performance loss caused by the random initialization,the pre-training method is employed to acquire a desirable initialization,which is used as the initial parameters of the training phase.Moreover,the initial DFO estimation is used as input along with the received pilots to further improve the estimation accuracy.Different from the training phase,the initial DFO estimation in pre-training phase is obtained by the data and pilot symbols.Simulation results show that the mean squared error(MSE) performance of the proposed method is better than those of the available algorithms,and it has acceptable computational complexity.

MIMO handset antenna for 5G/WLAN applications

We propose a dual-module multiple-input multiple-output(MIMO)antenna for portable terminals.The operating bands of the handheld terminal antenna are 5G(3.4–3.8 GHz)and WLAN(5.150–5.925 GHz).Antenna elements of 5G and WLAN are spaced to reduce coupling between antenna elements in the same module.The return loss of all antenna elements is larger than 6 dB.The isolation between all elements is larger than 14 dB.The radiation efficiency of the high-frequency antenna is greater than 50%,and the radiation efficiency of the low-frequency antenna is greater than 40%.The far-field gain of all elements is greater than 2.2 dBi.

Broadband V-band Radio over Fiber Uplink Fronthaul Transmission Using Cascaded Microwave Photonic Downconversion Topology

Exploiting microwave photonic(MWP)techniques to generate and distribute high-frequency millimeter-wave(mm-wave)signals,termed mm-wave radio over fiber(m-RoF)signals,holds considerable potential for achieving highdensity and high-capacity fifth-generation and beyond networks.Herein,we experimentally validate a broadband m-RoF uplink fronthaul transmission system using the MWP downconversion concept,which comprises receiving and processing radio-frequency(RF)signals in the unlicensed V-band at around 60 GHz.The proposed system harnesses the simple cascaded modulator topology,in which an ultrawideband off-the-shelf Mach–Zehnder modulator(MZM)renders a simplestructured remote radio head by directly encoding the broadband 60 GHz uplink RF signal into the optical carrier.The nonlinear transfer function of another MZM at the center unit is explored to achieve subharmonic downconversion using cost-effective low-frequency local oscillator signals.Based on proof-of-concept experiments,mm-wave four quadrature amplitude modulation orthogonal frequency-division multiplexing signals centered at frequencies ranging from 51 GHz to 70 GHz are successfully downconverted into signals at the intermediate frequency(IF)of 1.4 GHz.In the case of 1.2 m mm-wave,free-space,and 5 km m-RoF transmissions,the obtained IF signals with a total bandwidth of 2.4 GHz achieve a bit-to-error ratio performance lower than the 7%hard-decision forward error correction limit of 3.8×10^(−3).A gross bit rate of 10 Gbit/s can be achieved over a total spectrum of up to 10 GHz,which fully covers the globally unlicensed V-band of 57-66 GHz.

A novel grey wolf optimizer and its applications in 5G frequency selection surface design

In fifth-generation wireless communication system(5G),more connections are built between metaheuristics and electromagnetic equipment design.In this paper,we propose a self-adaptive grey wolf optimizer(SAGWO)combined with a novel optimization model of a 5G frequency selection surface(FSS)based on FSS unit nodes.SAGWO includes three improvement strategies,improving the initial distribution,increasing the randomness,and enhancing the local search,to accelerate the convergence and effectively avoid local optima.In benchmark tests,the proposed optimizer performs better than the five other optimization algorithms:original grey wolf optimizer(GWO),genetic algorithm(GA),particle swarm optimizer(PSO),improved grey wolf optimizer(IGWO),and selective opposition based grey wolf optimization(SOGWO).Due to its global searchability,SAGWO is suitable for solving the optimization problem of a 5G FSS that has a large design space.The combination of SAGWO and the new FSS optimization model can automatically obtain the shape of the FSS unit with electromagnetic interference shielding capability at the center operating frequency.To verify the performance of the proposed method,a double-layer ring FSS is designed with the purpose of providing electromagnetic interference shielding features at28 GHz.The results show that the optimized FSS has better electromagnetic interference shielding at the center frequency and has higher angular stability.Finally,a sample of the optimized FSS is fabricated and tested.