排序方式: 共有90条查询结果,搜索用时 15 毫秒
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宽带ISDN网络以及无线技术的迅速发展使得对无线ATM网络的需求日益增加。本文介绍了无线ATM网络的拓扑结构与用于无线网络的媒体访问控制方式,分析了现有的用于无线ATM网络的MAC的标准的现状,根据ATM业务得出了无线ATM媒体访问控制(MAC)设计的探讨性的结论。 相似文献
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介绍了一种分层式一无线网络的结构,这种网络结构使得战术武器指挥,控制,通信与情报系统,在强干扰和大量移动用户的环境下,具有较强的抗干扰性和灵活性。 相似文献
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针对LDGM 码的稀疏矩阵构造复杂度较高的问题,提出了一种具有低复杂度的LDGM码随机稀疏矩阵构造算法,该算法既降低了编码的复杂度又保证了良好的性能.同时,针对LDGM码存在明显的错误平层的问题,引入了串行级联结构,并提出了一种改进的SCLDGM码译码算法,该算法将内译码器输出的错误信息看作是BEC信道的删除信息,利用该先验信息初始化外译码器的输入,从而进一步提高BER性能.通过对SCLDGM码编码系统模型的仿真,得到近优的内外编码速率组合和近优的内外码码重.仿真结果表明,本文提出的算法在保证低复杂度的前提下,可以获得良好的BER性能,并有效的降低了LDGM码错误平层. 相似文献
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A new structure of next generation integrated communication system was proposed, which is composed of space segment based
on satellites and terrestrial segment. Moreover, the characteristics of enhanced multiple access schemes based on orthogonal
frequency division multiplexing (OFDM) technique were analyzed for satellite links. However, OFDM is a doubtful candidate
as its higher peak-to-average power ratio (PAPR) that causes the distortion of high power amplifier (HPA). Furthermore, different
schemes were evaluated and compared in terms of the HPA nonlinearity and the link level performance in detail. And the pilot-aided
channel estimation and equalization techniques were also considered for analyzing the problem. Simulation results show that
the bit error rate (BER) and block error rate (BLER) performance of orthogonal frequency division multiple access (OFDMA)
outperforms that of single carrier-frequency division multiple access (SC-FDMA) for the satellite links in the proposed structure,
though discrete Fourier transform-spread OFDM DFT-S OFDM has low PAPR, especially the BER performance of OFDMA is 3.6 dB larger
than that of SC-FDMA at the target BER. 相似文献
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一种采用FEC和ARQ相结合的自适应差错控制方式 总被引:3,自引:0,他引:3
自动重发差错控制方式由于可靠性高,实现简单得到广泛应用,但在信道干扰较强时效率较低。本文提出一种采用前向纠错和自动重发相结合的自适应差错控制方式,以TMS32010为核心组成的差错控制电路实现大扩散度卷积码的编译,根据信道误码情况,系统可自动修改卷积码的扩散度,该电路与以HDLC规程为基础上的ARQ系统互连组成的自适应差错控制系统,可大大提高传输效率,适用高速数传的要求。 相似文献
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AMessageTransmissionProtocolofaMobileDataCommunicationNetworkGUXuemai;GUOQing;LIUZhong(顾学迈)(郭庆)(刘忠)(ResearchInstituteofCommun... 相似文献
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