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研究了移动Ad Hoc网络中的媒体接入控制问题. 首先, 基于IEEE 802. 11媒体接入控制协议, 提出了应用于MANET网络媒体接入控制的2个机制: 自适应回退窗转发优先机制(FPF)和多跳链邀请发送机制(MFCTI). FPF机制根据业务优先级自适应调整竞争窗大小, 而MFCTI机制则充分利用了网络层路由信息和无线传播的广播特性. 在此基础上对所提出的机制进行了仿真研究并与原IEEE 802. 11媒体接入控制进行了比较. 结果表明, 所提机制可以有效地提高网络吞吐率, 降低端对端迟延, 缓解网络局部拥塞, 从而提高了MANET网络的性能. 其另一优点是只需对IEEE 802. 11媒体接入控制作少量的补充和改动. 相似文献
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Spectrum sensing is the first step of cognitive radio (CR). In this area, previous researches mostly consider distributed
local nodes which are under identical channel conditions, hence uniform and fixed detection threshold is set with energy detector.
However, the distributions of nodes in real environments are not quite the same. In this paper, the optimal threshold to minimize
the total detection error over additive white Gaussion noise (AWGN) channel is derived firstly. Then the dynamic threshold
scheme is proposed to reduce the average total detection error. Simulations have shown that, with this scheme, sensing performance
is improved. 相似文献
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