共查询到20条相似文献,搜索用时 15 毫秒
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Wireless Personal Communications - In this paper, an exact performance analysis for the hybrid radio frequency/free space optical (RF/FSO) communication system based on receiver diversity combining... 相似文献
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研究了基于选择合并(SC)分集的混合激光/射频(FSO/RF)航空通信系统性能,该系统设计简单且在发射端无需信道状态信息(CSI)。激光链路服从平均孔径效应下的Exponentiated Weibull大气湍流分布模型,射频采用Nakagami-m衰落信道模型,推导求出混合FSO/RF航空通信系统接收端信噪比的累积分布函数,进一步利用Meijer′s G函数推导了混合FSO/RF通信系统中断概率以及平均误码率的闭合表达式,通过仿真对比分析了不同湍流强度、调制方式及分集通信方案对系统中断、误码性能的影响。仿真结果表明,混合FSO/RF航空通信系统有效地利用了FSO及RF链路在不同大气信道条件下的互补性质,具有更优的中断和误码性能;采用BPSK调制能有效降低大气湍流对混合FSO/RF航空通信系统的影响;信噪比高时,并行传输、分集接收的通信方案对系统误码性能的改善要优于低阶调制对误码性能的改善。 相似文献
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Cellular wireless systems, such as mobile systems and fixed wireless access systems may encounter the problem of limited availability, where users of the system do not enjoy equal access opportunity to the systems' radio ports. The problem of limited availability was encountered in the early age of telephony but it has not yet been analyzed in the context of its impact on wireless system capacity. Two common scenarios where limited availability is encountered are discussed in this paper. One where there is an overlap in the coverage of two neighboring stations and the other where the coverage of one radio port is completely contained within that of the other. The paper analyzes two possible policies of radio port selection for the users who can access more than one port. One access policy is that of a completely random choice, while by the other the user selects only one of the free ports. The analysis demonstrates that system capacity may drop substantially if a proper balance is not maintained. 相似文献
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火控雷达的可靠性及使用性能直接影响到武器系统的机动能力、生存能力和作战能力。在火控雷达试验中也是一项重要鉴定项目。本文对火控雷达的可靠性试验方法及使用性能的评估作了粗浅探讨。 相似文献
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设计了一种在大气湍流和指向误差影响下的带有能量收集的混合双向RF/FSO中继传输系统。RF信号部分采用能量分割的方式进行能量收集,FSO信号部分则将其信号中的直流电分量所携带的能量收集起来存储在中继器中。其中射频RF链路采用Nakagamim信道衰落模型,自由空间光FSO链路采用Gamma Gamma信道衰落模型。并且计算出了两条链路各自的累积分布函数CDF。采用DF的中继协作方式,并利用Meijei G函数推导出系统中断概率的闭合表达式,最终通过仿真来验证结果的正确性。 相似文献
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提出了一种构建面向服务(SOA)的系统,以及对既有系统的服务提取及可用性评价的方法.通过对既有系统可提取的服务、与外部系统交换数据是需要的服务之间关系的分析,提出了既有系统的可利用性评价方法和模型.然后,对此方法步骤进行了论证,通过数学方法提出了一个定量的对既有系统整体可利用性的评价指标.利用此方法,可以规范既有系统服务提取的设计过程,并且能对既有系统的可利用价值进行一定的评判. 相似文献
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Photonic Network Communications - Radio frequency (RF) spectrum is already dense enough and hard to add more broadband channels to meet the current user demands. Optical free-space communications... 相似文献
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利用C++ Builder编程软件提供的相关网络组件,提出了基于网络丢包率的混合FSO/RF系统切换判决机制,在网络中实现了对链路的监控功能,并采用无线路由器、光纤收发器等器件搭建了混合FSO/RF测试系统,对基于网络丢包率的混合系统切换机制进行了测试,结果表明采用网络切换判决方案,能够自动选择链路通信,保证数据不间断... 相似文献
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Energy management system (EMS) computer architectures have changed significantly over the recent past increasing the difficulty and the need for a priori assessment of system performance and dependability. The old practice based on measurements is no longer acceptable because of the flexibility accrued with the deployment of the new distributed computer-based systems. The number of “what if” questions increased since EMS systems are now implemented using multiple workstations that can be interconnected in various different ways.In this paper we show how alternative configurations can be modeled and analyzed, before proposing and purchasing any equipment, with the assistance of Markov reward models. We review the concept of Markov reward models and show how they can be applied in the availability analysis of SCADA/EMS computer systems. The paper also presents a software tool that facilitates automatic generation and solution of large Markov reward models. The input language of this modeling tool uses a variation of stochastic Petri nets called stochastic reward nets, which are also reviewed. We believe this is the first time a detailed quantitative model of a SCADA/EMS computer system is proposed and solved in the general literature. 相似文献
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分析了远距离支援干扰有效性的影响因素.根据设置的作战环境进行了仿真计算,具体分析了在执行远距离支援干扰时应该考虑的问题。 相似文献
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分析了单脉冲雷达的工作原理和特点.具体研究了各种干扰样式的有效性因素,重点分析了同一平台内两点源相关干扰技术和方法,进行了仿真计算。 相似文献
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Shrivastava Shreesh Kumar Sengar Sujata Singh Shree Prakash 《Photonic Network Communications》2019,37(1):53-62
Photonic Network Communications - Hybrid FSO/RF communication systems make use of an RF link with OWC link to achieve higher reliability along with high data rate communication. Both these (OWC and... 相似文献
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王进才 《电子产品可靠性与环境试验》2010,28(4):1-5
使用可用度是军用直升机战备完好性的重要度量标准。文章基于仿真语言Matlab而构建了武器装备完好率与维修保障模型,并给出了仿真结论以及今后应进一步研究的问题。 相似文献