Device Discovery in D2D Communication: Scenarios and Challenges

Device to Device (D2D) communication is expected to be anessential part of 5G cellular networks. D2D communication enables closeproximitydevices to establish a direct communication session. D2D communicationoffers many advantages, such as reduced latency, high data rates,range extension, and cellular offloading. The first step to establishing a D2Dsession is device discovery;an efficient device discovery will lead to efficientD2D communication. D2D device further needs to manage its mode of communication,perform resource allocation, manage its interference and mostimportantly control its power to improve the battery life of the device. Thiswork has developed six distinct scenarios in which D2D communication canbe initiated, considering their merits, demerits, limitations, and optimizationparameters. D2D communication procedures for the considered scenarioshave been formulated, based upon the signal flow, containing device discovery,resource allocation, and session teardown. Finally, latency for each scenariohas been evaluated, based on propagation and processing delays.

高通公司Device to Device技术国内专利布局现状研究

本文对高通公司在4G演进技术--移动终端设备间直接通信技术(D2D技术)国内专利申请概况进行了研究,对其在D2D技术领域的专利布局情况进行了分类和统计,初步分析和阐述了高通公司在该领域的专利积累情况。根据其近年的专利技术方案,概要性地整理了其技术发展路线,为我国国内企业在该领域的研究和标准化策略提供参考。

Feedback-based unequal error protection fountain code over device-to-device broadcast

To enhance encoding efficiency, an unequal error protection （UEP） broadcast scheme based on one additional feedback is proposed. Different from the equal probability selection for source packets in traditional fountain encoding, the proposed scheme calculates the packet loss ratio （PLR） according to the feedback results in systematic broadcast phase （SBP） and then optimizes the selection probability for source packets to guarantee higher level error protection for those source packets with larger PLRs. Thus the amount of unnecessarily redundant encoded packets during encoding broadcast phase （EBP） is decreased significantly. Numerical results show that the proposed scheme can recover 60% more packets than the traditional non-feedback broadcast scheme at the ex- pense of tolerably only one feedback procedure.

Interference Suppression for MIMO Device to Device Pairs Underlaying Cellular Network

Device to device(D2D) communications may generate interference to the existing cellular networks.An interference suppression(IS) scheme is proposed in this paper.With this scheme,the threshold of D2D-pairs(D2D-Ps) communication was designed to reject the D2D-Ps which were not satisfied the threshold constraint,ensuring that the cellular users(CUs) had priority to use the spectrum resources.Then the interference from D2D-Ps at the receiver of CUs was eliminated first by precoding at the D2D transmitter and decoding at the CU's receiver.Next,the interference between D2D-Ps was suppressed by using interference alignment(IA).Performance analysis shows that the priority of CUs using the spectrum resources has been guaranteed;the interference generated on the cellular links is well eliminated;the interference between D2D-Ps can also be suppressed.

Recent Progress in the Fabrication, Properties, and Devices of Heterostructures Based on 2D Materials

With a large number of researches being conducted on two?dimen?sional(2D) materials, their unique properties in optics, electrics, mechanics, and magnetics have attracted increasing attention. Accordingly, the idea of combining distinct functional 2D materials into heterostructures naturally emerged that pro?vides unprecedented platforms for exploring new physics that are not accessible in a single 2D material or 3D heterostructures. Along with the rapid development of controllable, scalable, and programmed synthesis techniques of high?quality 2D heterostructures, various heterostructure devices with extraordinary performance have been designed and fabricated, including tunneling transistors, photodetectors, and spintronic devices. In this review, we present a summary of the latest progresses in fabrications, properties, and applications of di erent types of 2D heterostruc?tures, followed by the discussions on present challenges and perspectives of further investigations.

Radiotherapy-customized head immobilization masks:from modeling and analysis to 3D printing

Immobilization devices may be a valuable aid to ensure the improved effectiveness of radiotherapy treatments where constraining the movements of specific anatomical segments is crucial. This need is also present in other situations, specifically when the superposition of various medical images is required for fine identification and characterization of some pathologies. Because of their structural characteristics, existing head immobilization systems may be claustrophobic and very uncomfortable for patients, during both the modeling and usage stages. Because of this, it is important to minimize all the discomforts related to the mask to alleviate patients’ distress and to simultaneously guarantee and maximize the restraint effectiveness of the mask. In the present work, various head immobilization mask models are proposed based on geometrical information extracted from computerized tomography images and from 3D laser scanning point clouds. These models also consider the corresponding connection to a radiotherapy table, as this connection is easily altered to accommodate various manufacturers’ solutions. A set of materials used in the radiotherapy field is considered to allow the assessment of the stiffness and strength of the masks when submitted to typical loadings.

Light–matter interaction of 2D materials:Physics and device applications

In the last decade, the rise of two-dimensional （2D） materials has attracted a tremendous amount of interest for the entire field of photonics and opto-electronics. The mechanism of light-matter interaction in 2D materials challenges the knowledge of materials physics, which drives the rapid development of materials synthesis and device applications. 2D materials coupled with plasmonic effects show impressive optical characteristics, involving efficient charge transfer, plas- monic hot electrons doping, enhanced light-emitting, and ultrasensitive photodetection. Here, we briefly review the recent remarkable progress of 2D materials, mainly on graphene and transition metal dichalcogenides, focusing on their tunable optical properties and improved opto-electronic devices with plasmonic effects. The mechanism of plasmon enhanced light-matter interaction in 2D materials is elaborated in detail, and the state-of-the-art of device applications is compre- hensively described. In the future, the field of 2D materials holds great promise as an important platform for materials science and opto-electronic engineering, enabling an emerging interdisciplinary research field spanning from clean energy to information technology.

基于JXTA的无线D2D通信系统的研究与实现

移动通信技术的迅速发展使得频谱资源日益紧缺,人们对了解附近感兴趣的事物并与之通信的需求日渐增加,这些问题对现有的通信方式提出了挑战。D2D通信在系统的控制下复用小区资源,能够减小小区网络的负载,实现端到端直接通信及资源共享。研究并设计实现了以JXTA协议为基础、以WiFi为通信媒质、以AndroidOS为运行平台的无线D2D通信系统。

Black-phosphorus-based junctions and their optoelectronic device applications

Black phosphorus(BP)has attracted significant attention owing to its unique structure and preeminent photoelectric properties,which can be utilized to create novel junctions.Based on different BP-based junctions,versatile optoelectronic devices have been fabricated and investigated in recent years,providing a fertile library for the characteristics of BP-based junctions and their optoelectronic applications.This review summarizes diverse BP-based junctions and their optoelectronic device applications.We firstly introduce the structure and properties of BP.Then,we emphatically describe the formation,properties,and optoelectronic device applications of the BP-based junctions including heterojunctions of BP and other two-dimensional(2D)semiconductors,BP p–n homojunctions,and BP/metal Schottky junctions.Finally,the challenge and prospect of the development and application of BP-based junctions are discussed.This timely review gives a snapshot of recent research breakthroughs in BP-based junctions and optoelectronic devices based on them,which is expected to provide a comprehensive vision for the potential of BP in the optoelectronic field.

Fuzzy mathematics and game theory based D2D multicast network construction

Device to device(D2 D) multi-hop communication in multicast networks solves the contradiction between high speed requirements and limited bandwidth in regional data sharing communication services. However, most networking models demand a large control overhead in eNodeB. Moreover, the topology should be calculated again due to the mobility of terminals, which causes the long delay. In this work, we model multicast network construction in D2 D communication through a fuzzy mathematics and game theory based algorithm. In resource allocation, we assume that user equipment(UE) can detect the available frequency and the fuzzy mathematics is introduced to describe an uncertain relationship between the resource and UE distributedly, which diminishes the time delay. For forming structure, a distributed myopic best response dynamics formation algorithm derived from a novel concept from the coalitional game theory is proposed, in which every UE can self-organize into stable structure without the control from eNodeB to improve its utilities in terms of rate and bit error rate(BER) while accounting for a link maintenance cost, and adapt this topology to environmental changes such as mobility while converging to a Nash equilibrium fast. Simulation results show that the proposed architecture converges to a tree network quickly and presents significant gains in terms of average rate utility reaching up to 50% compared to the star topology where all of the UE is directly connected to eNodeB.

Nanoscale All-Oxide-Heterostructured Bio-inspired Optoresponsive Nociceptor

Retina nociceptor,as a key sensory receptor,not only enables the transport of warning signals to the human central nervous system upon its exposure to noxious stimuli,but also triggers the motor response that minimizes potential sensitization.In this study,the capability of two-dimensional all-oxide-heterostructured artificial nociceptor as a single device with tunable properties was confirmed.Newly designed nociceptors utilize ultra-thin sub-stoichiometric TiO2–Ga2O3 heterostructures,where the thermally annealed Ga2O3 films play the role of charge transfer controlling component.It is discovered that the phase transformation in Ga2O3 is accompanied by substantial jump in conductivity,induced by thermally assisted internal redox reaction of Ga2O3 nanostructure during annealing.It is also experimentally confirmed that the charge transfer in alloxide heterostructures can be tuned and controlled by the heterointerfaces manipulation.Results demonstrate that the engineering of heterointerfaces of two-dimensional(2D)films enables the fabrication of either high-sensitive TiO2–Ga2O3(Ar)or high-threshold TiO2–Ga2O3(N2)nociceptors.The hypersensitive nociceptor mimics the functionalities of corneal nociceptors of human eye,whereas the delayed reaction of nociceptor is similar to high-threshold nociceptive characteristics of human sensory system.The long-term stability of 2D nociceptors demonstrates the capability of heterointerfaces engineering for e ective control of charge transfer at 2D heterostructured devices.

3D tumor model biofabrication

Animal models have been extensively used in cancer pathology studies and drug discovery.These models,however,fail to reflect the complex human tumor microenvironment and do not allow for high-throughput drug screening in more human-like physiological conditions.Three-dimensional(3D)cancer models present an alternative to automated high-throughput cancer drug discovery and oncology.In this review,we highlight recent technology innovations in building 3D tumor models that simulate the complex human tumor microenvironment and responses of patients to treatment.We discussed various biofabrication technologies,including 3D bioprinting techniques developed for characterizing tumor progression,metastasis,and response to treatment.

Computer aided modeling and analysis of a new biomedical and surgical instrument

This paper describes the recent research and development of an endo surgical/biomedical instrument in surgical suture applications for minimally invasive therapy procedure. The newly developed instruments can not only protect the wound during the surgical procedure but also actively help the healing process. The new mechanism design of the surgical instrument aids in better ergonomic design, reliable functionality, and continuous cost reduction in product manufacturing. 3-D modeling technique, functionality analysis, kinematical simulation and computer aided solution have been applied to the instrument design, development and future improvement to meet the specific requirements of minimally invasive surgery procedure. The improved new endo surgical/biomedical instrument can prevent patient’s vessels and tissues from being damaging because the distal move of clips are well controlled without clip drop-off incident. Plus the operational force to form the clip is lower than regular surgical/biomedical instruments due to this special new mechanism design. In addition to the above, the manufacturing and product cost can be decreased because the dimensional tolerance of components, such as clip channel and jaw guide track, can be loose due to this new instrument design. The prototypes of this new endo surgical/biomedical instrument design are analyzed through computer aided modeling and simulation, in order to prove its feasible functionality, reliable performance, and mechanical advantage. All these improved features have also been tested and verified through the prototypes.

苹果采摘机器人末端设计及运动仿真

苹果在我国农业生产中占有重要地位,不仅是最主要的经济果树之一,而且在产量、种植面积及出口量上均居世界第一。产量大、范围广、种植地形复杂、分布零散等因素造成了苹果采摘困难、不及时、损失大等一系列问题。为了实现苹果的时效化、无损化采摘,设计一种负压式五自由度采摘机器人,基于标准型D-H参数建模方法对机器人的正、逆运动学进行求解,并利用ADAMS软件并建立机械臂的虚拟样机,通过运动学与动力学仿真分析,最终获得末端吸口的运动位移、速度、加速度及各关节角速度、驱动力矩的变化曲线。通过分析变化曲线,验证了机器人满足工作要求,结构设计合理,运动过程平稳无振荡,同时也为后续的控制系统研究奠定了基础。

六面顶压机顶锤图像采集装置的设计及分析

为了对六面顶压机顶锤的裂纹缺陷进行检测,设计了一种狭小空间图像采集装置对六个顶锤锤面进行图像采集,给出了图像采集装置的整体结构。按照最短路径标准对装置采集图像路径进行优化,建立了距离矩阵模型,并利用遗传算法进行求解寻找最优路径,实现了六组顶锤锤面图像的快速采集。采用D-H法建立了装置的连杆参数模型,通过运动学分析,求出了装置的正运动学方程和逆运动学方程的解。最后利用MATLAB对装置进行仿真分析,验证了所设计装置的合理性。

子叶期穴盘移苗装置轨迹执行机构设计与运动学分析

目的:为了实现不同密度穴盘的批量移苗作业,设计一种多点取苗多点投放的穴盘幼苗移苗装置。方法:采用Solidworks软件建立移苗装置的三维模型,通过D-H坐标系建立移苗装置运动学模型,得到运动学方程,并在Adams软件中对移苗装置进行运动学仿真,得到位移、速度和加速度曲线。结果:该装置完成一次移苗作业时长为8 s,相邻两末端执行器X方向位移差为32.3 mm,Y方向位移等于取苗盘与放苗盘穴孔中心距在Y方向投影,为525 mm,Z方向位移比放苗盘高30 mm,速度最大值为515 mm/s,加速度最大值为840 mm/s^(2)。结论:本文设计的移苗装置对推动工厂化育苗的发展有重要意义。

Surface charge transfer doping for two-dimensional semiconductor-based electronic and optoelectronic devices

Doping of semiconductors,i.e.,accurately modulating the charge carrier type and concentration in a controllable manner,is a key technology foundation for modern electronics and optoelectronics.However,the conventional doping technologies widely utilized in silicon industry,such as ion implantation and thermal diffusion,always fail when applied to two-dimensional(2D)materials with atomically-thin nature.Surface charge transfer doping(SCTD)is emerging as an effective and non-destructive doping technique to provide reliable doping capability for 2D materials,in particular 2D semiconductors.Herein,we summarize the recent advances and developments on the SCTD of 2D semiconductors and its application in electronic and optoelectronic devices.The underlying mechanism of STCD processes on 2D semiconductors is briefly introduced.Its impact on tuning the fundamental properties of various 2D systems is highlighted.We particularly emphasize on the SCTD-enabled high-performance 2D functional devices.Finally,the challenges and opportunities for the future development of SCTD are discussed.

Ultrafast direct laser writing of 2D materials for multifunctional photonics devices [Invited]

Recently,fundamental properties and practical applications of two-dimensional(2D)materials have attracted tremendous interest.Micro/nanostructures and functional devices in 2D materials have been fabricated by various methods.Ultrafast direct laser writing(DLW)with the advantages of rich light-matter interactions;unique three-dimensional processing capability;arbitrary-shape design flexibility;and minimized thermal effect,which enables high fabrication accuracy resolution,has been widely applied in the fabrication of 2D materials for multifunctional devices.This timely review summarizes the laser interactions with 2D materials and the advances in diverse functional photonics devices by DLW.The perspectives and challenges in designing and improving laser-fabricated 2D material photonic devices are also discussed.

2D materials for intelligent devices

Neuromorphic intelligent hardware technologies have undergone rapid advancement during the past decade,with the goal of building intelligent devices and systems capable of overcoming challenges associated with conventional hardware.Realization of neuromorphic intelligent hardware depends on major advances in materials science,condensed matter physics,device physics and engineering.As a revolutionary discovery,two-dimensional(2D)materials with atomically-thin thickness and exceptionally high tunability introduce a new physical paradigm and show great promise in the development of intelligent devices.Here,we give prominence to three categories of tunable properties(i.e.,charge carrier,band structure,lattice structure)that are inherent for 2D materials and review their superiorities in constructing intelligent devices particularly in electronics and optoelectronics.Furthermore,we provide insight into how the unique physical mechanisms emerging in 2D materials offer a fertile ground for the design of diverse intelligence devices.