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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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将纠错编码技术应用于移动信道中,以改善由于信道快衰落造成的长突发误码,提高通信的可靠性的研究工作近年来已取得了许多进展。部分常用分组码在移动信道中的性能估计与计算机模拟工作也已完成。但这些码在一定“突发密度”下的纠突发能力是个有待深入研究的问题。本文根据典型移动信道的长突发误码特征,讨论了几种常用分组码在不同突发密度指标△_0下的纠突发错误能力,并给出了它们的计算机模拟结果。 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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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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流星余迹信道短时突发的特点使得流星突发通信呈现间歇性,在等待一颗适合的流星出现前往往需要等待很长的时间,同时由于流星突发通信的"足迹"和"热点"特性,使其通信距离受到限制。为解决上述问题,提出一种基于流星余迹通信的无线分组网,首先针对流星余迹信道特点给出了适合该网络的路由选择策略,其次介绍了工作流程,最后对分组长度进行了分析,并给出了仿真结果。 相似文献
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结合已有流星余迹理论和实测数据,提出一种判定是否存在流星余迹突发及其到达时间间隔服从哪种参数分布的方法,并用C++程序模拟,统计出时间间隔服从的参数分布形式,并利用该参数的分布规律进行流星余迹信道建模。信道建模时,判断流星余迹的发生类型,并对两种类型流星余迹发生的次数做了统计,得到了接收功率的衰落曲线,并与实测数据功率曲线进行分析比较,结果显示与实测数据基本符合。 相似文献
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为检验流星余迹通信设备及软件在实战化环境中的应用效能,针对流星余迹通信信道规律复杂、实测代价高等问题,建立流星余迹信道仿真模型。通过对典型数学模型的深入研究,以欠密类流星余迹和过密类流星余迹信道模型为基础,融入了欠密类流星簇和多径信道两种特殊类型,按照概率论原理,建立了流星余迹信道混合模型,并结合流星余迹到达间隔模型,利用C++实现了流星余迹信道混合模型的仿真。该模型可生成包含单颗欠密类、单颗过密类、欠密类流星簇和多径信道等多种类型的复杂信道。仿真结果表明,所产生的流星余迹信道特征与实际信道基本相符,验证了该模型的可用性和合理性。 相似文献
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The use of error correction coding for meteor burst communications is discussed. The cutoff rate is derived for a meteor burst channel model which assumes that the received signal amplitude decays exponentially. The message error rate of a coded system, obtained by means of computer simulation, is compared to that of an uncoded system. A tight upper bound on the performance of the coded system is presented. It is shown that coding can reduce the signal-to-noise ratio (SNR) required for reliable communications via meteor bursts by many decibels. The coding gain is larger at shorter communication ranges where meteor trails, decay faster. It is also shown that the additional improvement achieved by providing the decoder with side information on the instantaneous level of the received signal is small 相似文献
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A computer investigation of error-control-coding techniques and bit error patterns recorded on an experimental Northern latitude meteor burst link is presented. Automatic repeat request (ARQ) and hybrid forward error correction (FEC) with ARC are examined from the standpoint of probability of message delivery and encountered message delivery delays. It is demonstrated that FEC will yield substantial improvement in the number of messages deliverable within a specified time constraint. Potential gains in extending the usable time duration of a meteor burst channel are on the order of factors of four with successful message delivery percentages increased by factors of 50 相似文献
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Jueping Cai Zan Li Xiaojun Chen Benjian Hao 《International Journal of Communication Systems》2011,24(6):745-760
In view of the characteristics of the meteor burst channel, the variable rate data transmission should be adopted to improve the system average throughput, which results in channel tracing and equalization problems at the receiver. Although the joint data and channel estimation of maximum likelihood sequence detection performing the principle of per‐survivor processing (PSP) is considered as an optimal detection scheme, its great computational complexity is a major problem and can hardly agree with the decreasing of the meteor channel. Based on the estimation of the system parameters, an adaptive state reduction of the PSP (ASRP) algorithm with only a few states in the trellis diagram is employed, while these states are chosen by the time‐varying threshold according to the exponential decay of meteor channels. It is shown that, ASRP can make a good tradeoff between the performance and the computational complexity, and provides reliable data transmission for adaptive modulation and coding of the meteor burst communication system. Computer simulation results and performance analysis are also included to support our developments. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
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High-latitude propagation phenomena, such as scatter from the aurora and sporadic-E propagation, can alter the communication characteristics of the meteor communication channel. This paper describes an experiment in which the fading and multipath profiles of the high-latitude meteor communication channel were characterized. The effects of high-latitude propagation phenomena on the capacity and reliability of meteor burst communication are discussed. 相似文献