一种基于流量需求的动态频谱分配算法

感知无线电是一个解决当前频谱资源紧缺情况的有效手段,其中动态频谱分配技术是一个非常重要的环节.文章首先建立了基于冲突图的需求分配模型,基于此模型提出了一种基于用户需求的动态频谱分配算法,在传统标签机制基础上增加了对感知用户随时间改变的频谱需求的支持.试验结果表明,当每个感知用户对频谱的需求随着时间的变化而变化并且为有限值的情况下,该算法能保证较好的公平性和提供较高的分配效率.     

由三角形投影问题再探椭圆面积

椭圆面积公式S=πab，其中π为圆周率，α、b分别是椭圆半短轴、半长轴的长．关于椭圆面积公式的证法有多种，文献[1]利用仿射变换与仿射不变量推导出椭圆面积公式，文献[2]通过对单位正方形的拉伸（压缩）变换前后面积关系的讨论，给出了椭圆面积公式的又一证法．文献[3]利用初等数学的方法，推导出椭圆面积的计算公式．本文利用投...     

Extracting cavity and pulse phases from limited data for coherent pulse stacking

Coherent pulse stacking(CPS) is a new time-domain coherent addition technique that stacks several optical pulses into a single output pulse, enabling high pulse energy and high average power. A Z-domain model targeting the pulsed laser is assembled to describe the optical interference process. An algorithm, extracting the cavity phase and pulse phases from limited data, where only the pulse intensity is available, is developed to diagnose optical cavity resonators. We also implement the algorithm on the cascaded system of multiple optical cavities,achieving phase errors less than 1.0°(root mean square), which could ensure the stability of CPS.     

Quantum anomalous Hall effect in real materials

Under a strong magnetic field,the quantum Hall(QH) effect can be observed in two-dimensional electronic gas systems.If the quantized Hall conductivity is acquired in a system without the need of an external magnetic field,then it will give rise to a new quantum state,the quantum anomalous Hall(QAH) state.The QAH state is a novel quantum state that is insulating in the bulk but exhibits unique conducting edge states topologically protected from backscattering and holds great potential for applications in low-power-consumption electronics.The realization of the QAH effect in real materials is of great significance.In this paper,we systematically review the theoretical proposals that have been brought forward to realize the QAH effect in various real material systems or structures,including magnetically doped topological insulators,graphene-based systems,silicene-based systems,two-dimensional organometallic frameworks,quantum wells,and functionalized Sb(111) monolayers,etc.Our paper can help our readers to quickly grasp the recent developments in this field.     

Transferring the stability of iodine-stabilized diode laser at 634 nm to radio frequency by an optical frequency comb

An optical flequency comb phase-locked on an iodine frequency stabilized diode laser at 634 nm is constructed to transfer the accuracy and stability from the optical domain to the radio frequency domain. An external-cavity diode laser is frequency-stabilized on the Doppler-free absorption signals of the hyperfine transition R（80）8-4 using the third-harmonic detection technique. The instability of the ultra-stable optical oscillator is determined to be 7 ×10^-12 by a cesium atomic clock via the optical frequency comb＇s mass frequencv dividing technique.     

Ultra-Stable Rubidium-Stabilized External-Cavity Diode Laser Based on the Modulation Transfer Spectroscopy Technique

We construct an ultra-stable external-cavity diode laser via modulation transfer spectroscopy referencing on a hyperfine component of the ST Rb D2 lines at 780 nm. The Doppler-free dispersion-like modulation transfer signal is obtained with high signal-to-noise-ratio. The instability of the laser frequency is measured by beating with an optical frequency comb which is phase-locked to an ultra-stable oven controlled crystal oscillator. The Allan deviation is 3.9 × 10-13 at I s averaging time and 9.8 ×10-14 at 90s averaging time.     

感知无线电技术研究及现状分析

感知无线电把频谱策略从静态方式变为动态方式从而大大缓解资源紧张问题,感知设备必须具有特殊的模块来支持该转变,并且导致了通信网络的许多新特点。文章还从空域、时域和频域方面分析了感知系统的干扰问题。最后对感知技术的传输模式作了探讨,并提出了有待进一步开展的工作。     

面向6G的通感算融合服务、系统架构与关键技术

5G系统主要面向通信服务而设计，并不是为原生支持通感算融合服务而设计的。6G将原生地支持通信、感知和计算服务，成为支撑未来社会高效可持续发展的网络信息底座，赋能丰富多彩的未来新业务。为此，解释了通感算服务以及服务用例，并定义了不同服务对应的性能指标和效率指标。为满足通感算融合服务及其指标，给出了一种通感算融合的系统架构及其关键特征。感知数据传输和计算数据传输既不同于通信的用户面数据传输，也不同于通信的控制面数据传输，进而提出了面向通感算融合的数据面，以解决通感算融合业务的数据传输需求。进一步地，面向通算融合，给出了6G通算融合基本流程，并给出了6G通算融合方案与算力网络协同的三种选项。面向通感融合，简要介绍了通感一体化的9个关键技术。还对感知和计算的“对外服务”和“对内服务”的逻辑关系进行了阐述。最后，给出了通感算融合的未来研究方向。