UAPM: An Urgency-Aware Packet Management for Disaster Management Using Flying Ad-Hoc Networks

The ever increasing demand of adhoc networks for adaptive topology and mobility aware communication led to new paradigm of networking among Unmanned Aerial Vehicles(UAVs)known as Flying ad-hoc Networks(FANETs).Due to their dynamic topology,FANETs can be deployed for disaster monitoring and surveillance applications.During these operations,UAVs need to transmit different disaster data,which consists of different types of data packets.Among them there are packets which need to be transmitted urgently because of the emergency situation in disaster management.To handle this situation,we propose a methodology of disaster data classification using urgency level and based on these urgency levels,priority index is assigned to data packets.An approach of Urgency Aware Scheduling(UAS)is proposed to efficiently transmit high and low priority packets with minimum delays in transmission queue.We take into account different scenarios of UAVs for disaster management and for N number of UAVs,we propose bio-inspired mechanism using behavioral study of bird flocking for cluster formation and maintenance.Furthermore,we propose a priority based route selection methodology for data communication in FANET cluster.Simulationresults show that our proposed mechanism shows better performance in the presence of evaluation benchmarks like average delay,queuing time,forward percentage and fairness.

Predictive Decision and Reliable Accessing for UAV Communication in Space-Air-Ground Integrated Networks

The cooperation of multiple Unmanned Aerial Vehicles(UAVs) has become a promising scenario in Space-Air-Ground Integrated Networks(SAGINs) recently due to their widespread applications,where wireless communication is a basic necessity and is normally categorized into control and nonpayload communication(CNPC) as well as payload communication. In this paper, we attempt to tackle two challenges of UAV communication respectively on establishing reliable CNPC links against the high mobility of UAVs as well as changeable communication conditions, and on offering dynamic resource optimization for Quality-of-Service(QoS) guaranteed payload communication with variable link connectivity. Firstly, we propose the concept of air controlling center(ACC), a virtual application equipped on the infrastructure in SAGINs, which can collect global information for estimating UAV trajectory and communication channels. We then introduce the knapsack problem for modelling resource optimization of UAV communication in order to provide optimal access points for both CNPC and payload communication. Meanwhile, using the air controlling information, predictive decision algorithm and handover strategy are introduced for the reliable connection with multiple access points. Simulation results demonstrate that our proposal ensures an approximate always-on reliable accessing of communication links and outperforms the existing methods against high mobility,sparse distribution, and physical obstacles.

On Connectivity of Flying Ad Hoc Networks in the Presence of Ground Terminal

The Unmanned Aerial Vehicle(UAV)technologies are envisioned to play an important role in the era of Air-Space-Ground integrated networks.In this paper,we investigate the connectivity of a Flying Ad hoc Network(FANET)in the presence of a groundbased terminal.In particular,the connected probability of the UAV-to-UAV (U2U) link as well as that of the UAV-to-Ground (U2G) link in a three dimensional (3D) space are analyzed.Furthermore,to mitigate the aggregate interference from UAV individuals,a priority based power control scheme is implemented for enhancing the connectivity of both U2U and U2G links.Numerical results illustrate the effectiveness of the proposed analysis.

5G ENTERING INTO A NEW ERA

The ever increasing wireless data services, such asimaging, video, audio, multimedia, etc., have de-mands for the very high speed wireless communicationsand network, which are unfortunately a bottleneck whencombining with the wireline core network. Users＇ arenow expecting high quality of experience with low-costdevices, ubiquitous connectivity, energy efficiency, highreliability, or even ultra-low latency if a vehicle terminalis applied.

Pyropia haitanensis polysaccharide extends lifespan by inhibiting protein aggregation in Caenorhabditis elegans

Pyropia haitanensis polysaccharide(LP)have been found for having many excellent functions such as anti-aging.Using Caenorhabditis elegans models,we evaluated the anti-aging activity of LP by observing the lifespan,reproduction,pharyngeal pumping,stress response,quantitative fluorescence of polyglutamic acid,and nuclear localization of DAF-16 of worms.The results reveal that LP could extend the adult lifespan of wild-type and polyQ nematodes,indicating a connection of its anti-aging benefit with the toxicity-suppressing effect.The number of polyglutamic acid aggregates in high concentration groups decreased by 24.39%(P<0.05)to the control.The high-dose group strongly induced DAF-16 nuclear translocation over intermediate and cytosolic localizations compared with the control(P<0.001).Therefore,we believe that LP could extend the lifespan and reduce the protein aggregation in C.elegans through nuclear DAF-16∷GFP expression.

A Novel Angle of Arrival Tracking Method in Large-Scale-Array Systems

In this paper,we investigate the problem of angle of arrival(AOA)tracking for the largescale array in terahertz(THz)communication,which has a large size and a narrow beam,highly demanding an accurate angle estimation.On the one hand,the system usually adopts a hybrid structure with limited radio-frequency(RF)chains,which increases the difficulty of angle estimation;on the other hand,the rapid mobility of users also brings new challenges to angle estimation.To address the above challenges,a two-stage tracking framework is proposed in this paper,which employs the random phase matrix and orthogonal long pilots in the first stage to reduce the complicated multi-user estimation to multiple single-user estimations,followed by using both wide and narrow beams in the second stage to serve high-speed and low-speed users.Furthermore,a generalized-approximated-message-passing(GAMP)method is proposed for facilitating a low-accuracy estimation of the angles,followed by adopting a modified expectation-maximization(EM)algorithm based phase estimation to unbiased estimate the instantaneous angle with the help of high-gain characteristics of the beams.The proposed structure can not only simplify the estimation complexity,but also improve the estimation accuracy due to its capability of transferring the non-linear problem of angle observation into a linear gaussian model.In addition,the Kalman tracking framework is employed for performing a continuous angle tracking.Numerical results show that the angle estimation based on the random phase matrix in the initial stage can obtain a high enough estimation accuracy,while the GAMP algorithm implemented in the second stage can quickly capture the angle range under the Rayleigh limit.The performance of the proposed EM-based tracking method is shown to outperform the traditional extended Kalman filter(EKF)method.

FULL-DUPLEX WIRELESS COMMUNICATIONS

Just as Dickens wrote,it is the best of times,it is the worst of times.Ever increasing traffic demands will bring us into the era of 5G.Vast of unprecedented or even unanticipated fancy wireless applications will definitely change our life.Regarding the beautiful visions promised by 5G,meanwhile the wireless engineers are faced with unprecedented challenges and pressures for realizing much higher spectrum efficiency and

OFDMA Uplink Frequency Offset Estimation with Multi-Access Interference Mitigation

In this paper, we consider the frequency offset estimation for Orthogonal Frequency-Division Multiple Access (OF-DMA) uplink (UL) transmissions. We first analyze the negative effect of Multi-Access-Interference (MAI) on OFDMA UL, and then propose two interference reduction/elimination methods, i.e., the Reduced-Rank-Projector (RRP) and Shift-Sampling-Projector (SSP) methods, to eliminate/reduce the heavy MAI due to the frequency offsets. Finally, we propose a new training sequence group named the Round-Robin Training Sequence Group (RRTSG), which has a high interference mitigation capabilities for OFDMA UL transmission. The Cramer-Rao Lower Bound (CRLB) for an unbiased frequency offset estimator in a Multiple Access (MA) system is also derived. Numerical results show that the proposed methods are suitable to eliminate/mitigate the effect of the frequency offset on OFDMA UL transmission.

基于超图聚簇和干扰限制区域理论的全双工D2D车载通信资源管理方案

在蜂窝车用无线通信(cellular vehicular-to-everything,C-V2X)系统中,车辆快速移动导致D2D链路的网络拓扑不稳定,频繁重构的网络拓扑增加了同频干扰问题的复杂度和拓扑管理信令的数量,造成基站的计算能力和带宽资源浪费.本文建立以簇为核心的全双工D2D(full-duplex device-to-device,FD-D2D)车载通信模型,提出基于超图聚簇(hypergraph clustering,HG-C)和干扰限制区域(interference limited area,ILA)理论的FD-D2D车载通信资源管理方案.利用链路依赖度(degree of link dependence,DLD)和车辆用户(Vehicle users,VUE)的计算能力提高簇的生存时间,降低基站的开销.同时,利用动态功率控制和复用区域映射辅助基站分配资源,削弱复用相同蜂窝链路的V-D2D(vehicular device-to-device)链路间和对蜂窝链路的同频干扰,提高频谱效率.最后,基于交通仿真建模软件VISSIM产生实时交通流数据,从而验证本文所提资源管理方案,结果表明:基站承担的网络拓扑管理任务量至少降低50%,与传统蜂窝D2D车载通信相比,频谱平均复用次数增加0.5次以上,频谱效率增加10%.

Multicommodity Flow Modeling for the Data Transmission Scheduling Problem in Navigation Satellite Systems

Introducing InterSatellite Links(ISLs)is a major trend in new-generation Global Navigation Satellite Systems(GNSSs).Data transmission scheduling is a crucial problem in the study of ISL management.The existing research on intersatellite data transmission has not considered the capacities of ISL bandwidth.Thus,the current study is the first to describe the intersatellite data transmission scheduling problem with capacity restrictions in GNSSs.A model conversion strategy is designed to model the aforementioned problem as a length-bounded single-path multicommodity flow problem.An integer programming model is constructed to minimize the maximal sum of flows on each intersatellite edge;this minimization is equivalent to minimizing the maximal occupied ISL bandwidth.An iterated tree search algorithm is proposed to resolve the problem,and two ranking rules are designed to guide the search.Experiments based on the BeiDou satellite constellation are designed,and results demonstrate the effectiveness of the proposed model and algorithm.