针对锁频锁相器(Phase and Frequency Detector,PFD)应用于低信噪比、大频偏的条件,通过理论分析和仿真验证阐述了窗口类型对系统频偏捕获速度、范围、噪声门限及相位噪声抖动的影响机理.推导出等效相位噪声功率谱密度的表达式.证明了...针对锁频锁相器(Phase and Frequency Detector,PFD)应用于低信噪比、大频偏的条件,通过理论分析和仿真验证阐述了窗口类型对系统频偏捕获速度、范围、噪声门限及相位噪声抖动的影响机理.推导出等效相位噪声功率谱密度的表达式.证明了大窗口具有更低的噪声门限和更小的稳态相位抖动,但捕获速度较慢.为了提高捕获速度,对鉴相器输出值取极性运算得到改进的PFD算法.新算法不仅能增加鉴相增益提高捕获速度;还可以减少等效噪声功率谱密度降低相位抖动;同时新算法不需要乘法器便于硬件实现.最后新算法的性能通过仿真得到了验证.展开更多
在多小区无线局域网(Wireless Local Area Networks,WLAN)中,由于存在小区间接入访问点同频干扰,以及小区间同频用户干扰,其系统性能与单小区网络具有很大不同。本文提出了支持多种用户传输速率共存、支持用户非均匀分布的多小区WLAN系...在多小区无线局域网(Wireless Local Area Networks,WLAN)中,由于存在小区间接入访问点同频干扰,以及小区间同频用户干扰,其系统性能与单小区网络具有很大不同。本文提出了支持多种用户传输速率共存、支持用户非均匀分布的多小区WLAN系统吞吐率估计算法。通过对多小区WLAN巾接入访问点的布置、信道的配置进行仿真,结果表明即使在存在小区间同频干扰的情况下,估计算法也能得到满意的吞吐率估计结果。展开更多
The routing algorithm is one of the important problems in the Ad hoc networks. The performances of the networks are heavily depended on the property of the routing algorithm. In this paper, we present a new loop-free ...The routing algorithm is one of the important problems in the Ad hoc networks. The performances of the networks are heavily depended on the property of the routing algorithm. In this paper, we present a new loop-free routing algorithm in the Ad hoc networks. By virtue of the correlation of routing information among neighbor nodes, the formation of the temporary loops during the topological changes can be prohibited. The new algorithm can avoid the waste of the wireless bandwidth, and accelerate the convergence of the routing during the network transitions.展开更多
文摘针对锁频锁相器(Phase and Frequency Detector,PFD)应用于低信噪比、大频偏的条件,通过理论分析和仿真验证阐述了窗口类型对系统频偏捕获速度、范围、噪声门限及相位噪声抖动的影响机理.推导出等效相位噪声功率谱密度的表达式.证明了大窗口具有更低的噪声门限和更小的稳态相位抖动,但捕获速度较慢.为了提高捕获速度,对鉴相器输出值取极性运算得到改进的PFD算法.新算法不仅能增加鉴相增益提高捕获速度;还可以减少等效噪声功率谱密度降低相位抖动;同时新算法不需要乘法器便于硬件实现.最后新算法的性能通过仿真得到了验证.
文摘在多小区无线局域网(Wireless Local Area Networks,WLAN)中,由于存在小区间接入访问点同频干扰,以及小区间同频用户干扰,其系统性能与单小区网络具有很大不同。本文提出了支持多种用户传输速率共存、支持用户非均匀分布的多小区WLAN系统吞吐率估计算法。通过对多小区WLAN巾接入访问点的布置、信道的配置进行仿真,结果表明即使在存在小区间同频干扰的情况下,估计算法也能得到满意的吞吐率估计结果。
文摘The routing algorithm is one of the important problems in the Ad hoc networks. The performances of the networks are heavily depended on the property of the routing algorithm. In this paper, we present a new loop-free routing algorithm in the Ad hoc networks. By virtue of the correlation of routing information among neighbor nodes, the formation of the temporary loops during the topological changes can be prohibited. The new algorithm can avoid the waste of the wireless bandwidth, and accelerate the convergence of the routing during the network transitions.
