共查询到20条相似文献,搜索用时 15 毫秒
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TD-LTE是下一代移动通信网络的主流技术之一,本文首先描述了TD-LTE无线网络规划流程,然后对TD-LTE覆盖及容量特性进行了重点分析,给出了TD-LTE试验网络建设的覆盖及容量规划建议。 相似文献
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在介绍了现有随机序列的优缺点以及分析随机序列主要产生方法的基础上,提出了一种基于循环替换原理的伪随机序列产生方法,并用FPGA加以实现。该方法产生的伪随机序列完全符合FIPS140-2标准,并具有周期长、线性复杂度高、相关性好以及产生时间短的特性,能广泛应用于信息安全等系统中。 相似文献
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该文基于直扩系统原理,建立了PN序列直扩系统仿真模型,利用Matlab工具仿真分析了系统在宽带干扰、单音干扰和脉冲干扰下的性能,并对编码和同步对系统误码性能的影响作了仿真研究,最后总结了直扩抗干扰性能。 相似文献
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相关跳频序列的Viterbi译码算法及其纠错性能分析 总被引:4,自引:2,他引:4
该文分析了相关跳频通信系统中频率转移函数的纠错性能,将Viterbi算法应用于接收端跳变频点序列的译码,并结合相关跳频转移函数的特点对译码过程作出了改进.针对满足最大相关纠错性能的频率转移函数,详细分析了Viterbi算法的译码性能.仿真结果表明,通过相关纠错,对随机错误在低信噪比条件下可以获得5-8dB的增益. 相似文献
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Ferrari P. Flammini A. Marioli D. Taroni A. 《Industrial Informatics, IEEE Transactions on》2008,4(1):16-25
Ethernet technology is widely used in real-time industrial automation. Thanks to real-time Ethernet (RTE) protocols, defined in IEC61784-2 standard, new top-performance automation solutions can be created. Such systems may have communication cycle time down to tens of mus and cycle jitter less than 1 mus, making network testing and debugging very critical. Existing network and protocol analyzers can perform detailed local analysis, but characterization of high-performance RTE systems requires measurement of transmission delays and these instruments cannot be adequately synchronized among them to realize a distributed measurement network. This paper introduces a new low-cost distributed measurement instrument to measure timing characteristics of RTE nodes (end-to-end delays, synchronization, etc.). The proposed instrument has multiple FPGA-based probes that allow for simultaneous/synchronized logging on different place of the target RTE network. A PC-based "monitor station" stores all the data, ready for further elaboration. Architecture details are discussed, a prototype has been realized, and some experimental results are presented. For instance, synchronization accuracy between probes is below 100 ns. 相似文献
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伪随机序列在流密码、信道编码和扩频通信等领域有着广泛的应用,m序列是重要的伪随机序列.文中首先对m序列的原理、结构及性质进行分析,然后通过matlab仿真实现m序列,并对其相关特性进行仿真,结果表明该方法的正确性和可行性. 相似文献
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在一般跳频系统中,跳频序列是由递归算法产生的,如PN序列以及混沌序列、模糊序列等。本文介绍的基于时钟和地址的跳频序列提供了一种新的产生方法。这种序列是由长比特设备地址和不断变化的长比特时钟信息经过一系列运算而产生的,即基于时钟和地址和跳频序列,该序列具有理想的均匀频谱特性和很长的周期;序列线性跨距很长,不容易被智能干扰机干扰;序列的汉明相关特性也很好;这个特点在多址接入通信中非常有用。该序列另一个重要特征是硬件实现简单容易,事实上,这种序列巳成功应用于蓝牙跳频系统中。本文主要介绍这种跳频序列的设计产生过程,并对序列的各种性能进行分析。 相似文献
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In this paper, we present an improved multicarrier direct sequence (DS) code division multiple access (CDMA) scheme by modifying the system originally proposed by Kondo and Milstein [13]. In this modified system, different spreading sequences multiplied by a data sequence modulate different carriers. This is to prevent the multiple access capability from reducing when the fading characteristics of different carrier frequencies are highly correlated. We have derived a formula which determines the mean values of the relative received signal strength in a single carrier DS CDMA rake system and in a multicarrier DS-CDMA system. We present results on the comparison of the bit error rate (BER) performance of the two systems including the effect of correlation between fading characteristics of different frequencies under various multipath fading conditions. The results indicate that with 50 users the modified multicarrier DS CDMA system can achieve an uncoded irreducible BER of 1.7 × 10??3 with an average received signal-to-noise ratio per bit of 10 dB, which is better than 3.0 × 10??3 achieved by the single carrier DS CDMA rake system, and also show that if multicarrier CDMA system is used with respect to single carrier CDMA system, the SNR gain is up to 4.5 dB for the uncode BER of 10??3 being achieved. 相似文献
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一类新的性能优越的伪随机序列* 总被引:3,自引:0,他引:3
本文提出了一类新的P元(P为任意素数)的伪随机序列(称为Lz序列)的构造方法。证明了所构造的序列具有理想自相关特性;通过计算还表明该序列是平衡的非线性序列,序列的等效线性长度可以很长。 相似文献
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Logistic满映射混沌序列性能分析 总被引:2,自引:0,他引:2
通过建立Logistic满映射混沌模型,产生Logistic满映射混沌模拟序列,再进行二值量化后,利用Matlab7.0对其性能进行仿真分析。主要分析其初值敏感性、相关性、平衡性、遍历性、相空间及倍周期分岔特性。分析结果表明,Logistic满映射混沌序列具有良好的自相关性、互相关性、平衡性,而且其序列数量众多,其性能优于传统的伪随机序列。该序列可广泛用于数字加密、扩频通信等领域中。 相似文献
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《Industrial Electronics, IEEE Transactions on》2009,56(8):2894-2903