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36871.LEO卫星通信中多普勒频移估计与补偿的硬件实现
[信息传输、软件和信息技术服务业] [2014-04-14]
In the low earth orbit (LEO) satellite communication systems,in which receiver and transmitter are not fixed and have significant relative velocity,the fast time-varying Doppler frequency shift is high,which degrades the performance of acquisition and tracking.Doppler frequency shift and Doppler frequency rate can be calculated by the terrestrial system based on the satellite orbit and the relative velocity.In this paper,we introduce the Doppler compensation principle and the realization of Doppler shift estimation and compensation on an universal wireless signal processing platform.The experimental results showed that the Doppler compensation model have high accuracy,which is positively correlated with the Doppler frequency rate.
关键词：通信；卫星通信；近地轨道；多普勒频移；多普勒补偿
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36872.使用地标照片匹配和智能字符识别的移动旅游规划
[信息传输、软件和信息技术服务业] [2014-04-14]
In this paper,we attempt to design a mobile application to assist visitors to have better understandings of popular tourist destinations and related routing information while on tour.The users can obtain descriptions of a specific attraction by simply taking the picture of a landmark photo often shown in the travel booklet using their mobile devices.This is achieved by matching the landmark picture with an image database containing popular tourist spots to locate the interested destination.The location information is further confirmed using techniques in intelligent character recognition.Upon successful identification of the interested location,tourist information regarding this destination,along with the routing details will be delivered using location-based service.We anticipate the proposed mobile application to effectively assist foreign visitors by bringing comprehensive,up-to-date tourist information and promoting better travel experience.
关键词：通信；移动设备；地标照片匹配；智能字符识别
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36873.卫星通信中的编码协作策略研究
[信息传输、软件和信息技术服务业] [2014-04-14]
Aiming at the satellite mobile communication,the cooperative communication technology is applied to the forward downlink in this paper,and one scheme with two satellites based on the coded cooperative which used the Alamouti space time block code is presented.Simulation results show the coded cooperative strategy can obtain better performance than the traditional uncoded systems,which is lower than the MIMO system with two transmit antennas and one receive antenna based on the Alamouti code,but the power of the terminal was decreased.It has the advantage in communication range and low complex mobile terminal,which has a certain application prospects in satellite mobile communications in the future.
关键词：通信；移动通信；编码协作；空时编码；Alamouti编码
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36874.船舶运动虚拟仿真中基于DCOM的组通信的应用
[信息传输、软件和信息技术服务业] [2014-04-14]
Virtual reality based visual interactive simulation system is proposed and completed,which applied integrated intelligent control to ship steering and main engine.For the multipoint communication of the proposed distributed visual simulation system,a DCOM based communication model is discussed.The group communications is divided into three layers from bottom to top.Based on static and dynamic combined algorithm,a dispatcher using centrality load balancing is also presented.
关键词：通信；DCOM；组通信；船舶运动虚拟仿真
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36875.水声通信的双曲频率调制信号（HFM）的多普勒估计和同步
[信息传输、软件和信息技术服务业] [2014-04-14]
This paper presents the application of the hyperbolic frequency modulated (HFM) signal to acoustic propagation in order to improve the performance of underwater acoustic (UWA) communications.Due to the large delay spread caused by multipath propagation and the severe Doppler Effect of the channel,we propose the using of double HFM signals as preambles for Doppler estimation,flame synchronization in UWA communications.A theoretical analysis about Doppler-invariability of HFM signals was provided firstly,then some numerical simulations about Doppler estimation were implemented,and experiments on testing performance of double-HFM preambles for frame synchronization in the pool were carried out as well.The simulation and experimental results show that using double-HFM signals as preambles has the capability to take an explicit Doppler estimation and retiming for frame synchronization,demonstrating that it has a good prospect in underwater acoustic communication system,especially for moving platforms.
关键词：通信；HFM信号；多普勒估计；水声通信
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36876.基于多核的并行处理技术的研究
[信息传输、软件和信息技术服务业] [2014-04-14]
In this paper,five kinds of typical multi-core processers are compared from thread,cache,inter-core interconnect and etc.Two kinds of multi-core programming environments and some new programming languages are introduced.Thread-level speculation (TLS) and transactional memory (TM) are introduced to solve the problem of parallelization of sequential program.TLS automatically analyze and speculate the part of sequential process which can be parallel implement,and then automatically generate parallel code.TM systems provide an efficient and easy mechanism for parallel programming on multi-core processors,Typical TM likes TCC,UTM,LogTM,LogTMSE and SigTM are introduced.Combined the TLS and TM can more effectively improve the sequential program running on the multi-core processors.Typical extended TM systems to support TLS likes TCC,TTM,PTT and STMiite are introduced.
关键词：通信；多核；并行编程环境的并行语言；TLS；TM；TLS+TM
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36877.超高速数据采集与存储系统的集成仪器
[信息传输、软件和信息技术服务业,计算机、通信和其他电子设备制造业] [2014-04-14]
Along with the rapid development of computer technology,high speed data acquisition and storage system has been widely applied in plenty of engineering fields,such as radar,aerospace industry,communication,etc.In order to satisfy the increasing requirement,we present the design structure of a novel integrated instrument for ultra-high speed data acquisition and storage,which is composed of ultra-high speed data acquisition,high speed data transmission and solid storage three main sub-systems.The detailed design and realization of the sub-systems are presented.We test and analysis the performance of the integrated instrument and the actual results show that the instrument performs stably and provides excellent speed and precision.
关键词：通信；超高速数据采集；数据存储；数据传输；集成仪器
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36878.浅海水声通信的速率兼容LDPC码的设计
[信息传输、软件和信息技术服务业] [2014-04-14]
In this paper,we propose rate-compatible LDPC (RC-LDPC) codes to improve the communication system reliability for SWA communications.The proposed SWA system adopting RC-LDPC codes consists of three important preprocessing:channel state information (CSI) estimator,signal-to-noise ratio (SNR) estimator and RC-LDPC pattern.For the estimation error,we define and derive the sensitivity to imperfect CSI and imperfect SNR.Then the design of RC-LDPC codes and SWA channel profile are described.Furthermore,the RC-LDPC performance pattern is given and sensitivity to estimation error of CSI and SNR are analyzed via simulation.It is shown that RC-LDPC codes have good performances with wide range of rates in SWA channels.Finally,coding rate distributions of RC-LDPC codes in different SNR at BER below 10-4 for SWA channel are investigated.
关键词：通信；速率兼容LDPC码；浅海水声通信；水声通信
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36879.认知无线电网络的联合功率分配和中继选择算法
[信息传输、软件和信息技术服务业] [2014-04-14]
This paper investigates the joint power allocation (PA) and relay selection scheme (RS) intwo-way relaying cognitive radio networks consisting of multiple user-pairs and multiple relays.In order to reduce the computational complexity for practical scenario,we propose a branch and bound based (BnB-based) power allocation and relay selection scheme and a greedy power allocation and relay selection scheme to maximize the system throughput.The system is assumed under the constraint that the interference power from the secondary nodes in two way relay systems to primary user (PU) shall be less than a predefined interference threshold which can guarantee the normal communication of PU.Numerical simulation results show that the optimal PA and RS scheme has the highest system capacity,however,the greedy PA and RS scheme has the lowest complexity.The proposed BnB-based PA and RS scheme has the better tradeoffofsystem throughput and complexity than the above two schemes.
关键词：通信；功率分配；中继选择；认知无线电网络
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36880.分布式推进控制的通信体系结构和网络拓扑结构比较
[信息传输、软件和信息技术服务业] [2014-04-14]
A distributed engine control system (DECS) offering flexibility and scalability is envisioned for the next generation of propulsion controls. Perhaps the most touted benefit of a DECS is the potential to reduce the amount of harnessing which connects throughout the engine. Such a system is comprised of several network sections incorporating control nodes or data concentrators (DCs). These DCs contain control logic to perform control function computations and are connected to the full authority digital engine control (FADEC) via a high-speed data communication bus. A novel approach for analyzing and evaluating three topologies; ring, star, and bus in the context of a relevant military engine was described. In this study, the algorithm uses a particle swarm optimization process to evolve solutions to a multi-objective optimization problem. The results of this study indicate there is potential for large wire length savings in a distributed control architecture.
关键词：通信；通信网络；推进系统；拓扑结构；军用飞机
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