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针对随机突发并且接收信号多数以指数衰减的流星余迹信道来说,研究链路自适应技术以达到充分利用流星余迹信道资源就显得尤为重要。深入研究了流星余迹突发通信的传播机理和信道的随机特性,从理论上经过分析计算证明了采用自适应变速率技术可以显著改善和提高流星突发通信性能,在此研究基础上提出了基于流星余迹动态信道估计的流星余迹自适应变速率通信技术解决方案。 相似文献
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流星余迹通信具有其他通信系统无法比拟的优点,如:大跨距、抗干扰、低截获概率特性和抗毁性等特点,使得这种通信方式的应用范围越来越广泛,尤其是支援短波通信及用作卫星通信的替补手段。但是流星余迹信道又是一种典型的突发信道,通信容量小和实时性差。为了最大限度地利用短暂的流星余迹信道,人们设计了链路自适应技术。此技术能够根据信道状况自动调整发射机和接收机的参数,使得流星余迹信道资源得到最大限度的利用。 相似文献
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流星余迹通信利用流星电离余迹对无线电波的反射和散射作用来进行通信,它是一种突发通信方式。流星余迹通信方式特殊,具有通信距离远、覆盖范围大、保密性强、通信信道不受电离层骚扰和极光等恶劣自然电磁环境的影响等特点,在未来战争中,流星余迹通信是一种理想的应急通信手段。另外流星余迹通信也特别适合于恶劣环境下的气象通信。介绍一种应用于小型移动载体的流星余迹突发通信系统的设计方案,并对其工作原理、关键技术及应用前景进行讨论。 相似文献
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讨论了流星突发通信欠密类余迹的信道特性及其模型。以TMS320VC5509 DSP为核心设计了流星信道模拟器系统,并给出模拟器在实验室流星突发通信自适应变速率系统设计中的测试应用。 相似文献
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流星余迹信道是一种典型的突发无线超视距信道,对流星突发通信系统的设计方案,使用模拟信道进行分析比较,有着简易、经济的优势。基于公认的流星突发信道的数学模型,通过合理假设,推导出适合建立计算机模型的数学表达式,由此编写Matlab程序,选取典型信道参数,实现了对流星突发信道的计算机模拟。 相似文献
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Tracy Bradley Maples Tatsuya Suda 《International Journal of Satellite Communications and Networking》1991,9(5):247-265
The increasing demand for communication services, coupled with recent technological advances in communication media and switching techniques, has resulted in a proliferation of new and expanded services. Currently, networks are needed which can transmit voice, data and video services in an application-independent fashion. Unified approaches employ a single switching technique across the entire network bandwidth, thus allowing services to be switched in an application-independent manner. This paper presents a taxonomy of integrated-service networks, including a look at NISDN, while focusing on unified approaches to integrated-service networks. The two most promising unified approaches are burst and fast packet switching. Burst switching is a circuit switching-based approach which allocates channel bandwidth to a connection only during the transmission of ‘bursts’ of information. Fast packet switching is a packet switching-based approach which can be characterized by very high transmission rates on network links and simple, hard-wired protocols which match the rapid channel speed of the network. Both approaches are being proposed as possible implementations for integrated-service networks. We survey these two approaches, and also examine the key performance issues found in fast packet switching. We then present the results of a simulation study of a fast packet switching network. 相似文献
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流星余迹通信具有间歇性、信道时变性的特点,大大限制了其网络稳定性和数据传输量,因此,如何提高流星余迹通信的稳定性和数据传输量,是流星余迹通信的关键技术之一。在多基站环状网络结构的基础上,将各基站用高速有线链路连成全连通网络以克服环状网络稳定性低的缺点,并且对基于停等协议传输的流星余迹通信网络,利用Opnet网络仿真工具搭建了网络仿真模型,对包长度和发包速率进行了分析,最后给出了仿真结果。 相似文献
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为了解决应用在高速突发通信场合的分组同步问题,介绍了一种基于自适应门限的快速分组同步技术,提出了基于自适应门限的算法和基于可编程逻辑器件(FPGA)的软件设计结构,给出了同步序列及其相关性仿真结果,分组同步相关峰和门限的定量分析和这种自适应门限算法在不同信噪比下的仿真曲线。该技术相比传统的分组同步搜索性能有明显的改善,具有同步序列短、传输效率高、实时性强、门限自适应以及同步稳定可靠等特点。 相似文献
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In this letter, we demonstrate a technique for suppression of transients in output bursts of an erbium‐doped fiber amplifier (EDFA) in an optical burst network. To suppress the transients, the EDFA is forward‐fed by non‐fluctuating input utilizing a power‐modulated burst control packet channel. Using the technique, we obtained a maximum 1.7 dB reduction in gain transient in the EDFA output, and we transmitted 9.953 Gbps data bursts and 2.488 Gbps burst control packets stably. 相似文献
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最佳小波包多载波调制解调技术 总被引:4,自引:0,他引:4
本文利用离散小波包变换(DWPT)导出信号窨的诱导小波包基。在此基础上建立起基于DWPT的小波包多载波传输系统的概念,提出了最佳小波包多载波市制解调技术。技术根据给定的信道特性,采用类似于最佳基搜索城众多的小波包多载波市制解调方案中快速寻求出最佳方案,使得系统解调出的信号中所要信号与符号间干扰的信干比在不增强噪声的前提下达了最大。 相似文献
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随着网络技术的发展,广泛互联互通的异构网络间的信息交互越来越频繁。为有效保障信息跨网安全实时交换,提出了一种抗隐蔽通道的网络隔离通信方案(NICS, network isolation communication scheme)。建立了NICS理论模型,基于信息论理论证明了该方案的正确性,并给出了具体的实施方案。安全特性分析表明,NICS可有效解决不同网络的通信协议均存在潜在的数据分组大小隐蔽通道与状态信息隐蔽通道的问题;在交互相同信息量的前提下,可实现与物理隔离等价的抗隐蔽通道的安全效果。 相似文献
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Fangqin Liu Tom H. Luan Xuemin Shen Chuang Lin 《Wireless Communications and Mobile Computing》2014,14(12):1160-1175
The packet loss burstiness over wireless channels is commonly acknowledged as a key impacting factor on the performance of networking protocols. An accurate evaluation of the packet loss burstiness, which reveals the characteristics and performance of the wireless channels, is crucial to the design of wireless systems and the quality‐of‐service provisioning to end users. In this paper, a simple yet accurate analytical framework is developed to dimension the packet loss burstiness over generic wireless channels. In specific, we first propose a novel and effective metric to characterize the packet loss burstiness, which is shown to be more compact, effective, and accurate than the metrics proposed in existing literature for the same purpose. With this metric, we then develop an analytical framework and derive the closed‐form solutions of the packet loss performance, including the packet loss rate and the loss‐burst/loss‐gap length distributions. Lastly, as an example to show how the derived results can be applied to the design of wireless systems, we apply the analytical results to devise an adaptive packetization scheme. The proposed packetization scheme adaptively adjusts the packet length of transmissions based on the prediction of the packet loss rate and loss‐burst/loss‐gap lengths of the wireless channel. Via extensive simulations, we show that with the proposed packetization scheme, the channel throughput can be enhanced by more than 10% than the traditional scheme.Copyright © 2012 John Wiley & Sons, Ltd. 相似文献