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1.
In order to solve the problem of ambiguous tracking and multipath mitigation of new signal time-multiplexed binary offset carrier modulated signal in the global navigation satellite system, this paper proposes an improved strobe correlation method which calculates the correlation of the received TMBOC signal with the W2 strobe waveform in 0.5 code offset and the pseudo-random code code in 0.5 code offset, respectively, and then the two correlations are multiplied. In this way an unambiguous and good symmetrical code discrimination curve is obtained. The characteristics of the obtained code discrimination curve by the proposed method is analyzed and simulated, and the result shows: the proposed method is easy to realize, and the obtained code discrimination curve has good central symmetry, strong multipath mitigation capability and can be used for an unambiguous tracking, so it is more suitable for the TMBOC signal discrimination compared with the existing strobe correlation methods and improved methods. 相似文献
2.
Aiming at the differentiated needs of users and the problem of video service interruption caused by the local overload of the converged network,a load-balanced video transmission mechanism is proposed.First,the split multipath routing protocol is improved to obtain the path selection model according to the front-end structural characteristics of the optical fiber wireless access network;second,we calculate the path differential delay and the video transmission delay on wireless side,and set their threshold as the quality of the experience constraint.Finally,while considering the quality of user experience,a particle swarm optimization algorithm with a multi-stage penalty function is used for video distribution.Simulation results show that the proposed mechanism is better than the throughput-aware load-sensing algorithms,enhances delay-control load distribution algorithms and delay-energy-quality aware multipath algorithms,and that it can effectively balance the network load and alleviate network congestion while avoiding user loss. 相似文献
3.
信道模拟器是近年来无线通信系统测试与性能评估中的新型测量仪器,研究了包含路径损耗、阴影衰落、多径衰落和信道噪声多种因素的无线信道模型,提出了一种基于谐波叠加原理且易于硬件实现的复合衰落信道实时模拟方法,并据此研制了中频信道模拟器原理样机。实测和分析结果表明,模拟器输出信道衰落分布与理论值非常吻合,统计方差的相对偏差约为0.06%,而自相关特性和多普勒功率谱也均与设计值吻合,可用于实验室模拟真实传播环境对无线信号的随机失真影响。 相似文献
4.
针对面向传统单光源无线光接入网络的分析性建模方案无法充分地适用于正在兴起的基于阵列式发光二极管(LED)光源的无线接入网络问题,提出了两种新的演进方案。第一种演进方案全面引入对各光源漫射分量的表征;第二种演进方案在前一方案基础上更精细化地引入对各漫射相对时延的考虑。两种演进方案都克服了现有的演进方案未考虑绝大部分光源所引入的漫射多径分量而高估信道基带传输特性的缺陷。量化结果显示,由于对漫射分量的充分考虑,避免对基带传输带宽的高估最高可达近50 MHz,避免传输幅度低估最高可达近15 dB。此外,两种演进方案能够表征接收位置、反射率以及接收端视场角(FOV)各自与传输特性的高度相关性,弥补了现有演进方案无法表征上述相关性的不足。 相似文献
5.
针对无线传感器网络(WSN)中多径路由的可靠性和能量效率问题,提出了一种基于代理和位置感知的多径路由发现方案(LABMR).事件节点根据位置信息,动态寻找其到Sink节点之间的特殊中间节点,来构建多径路由.利用移动代理来收集多径路由的局部拓扑结构信息,Sink节点根据代理收集的路由参数来计算路径权值,以此选择最优不相交路径.同时,对于信息的重要性差异,Sink节点选择单条或多条路径来传输数据,在保证传输可靠性的同时减少能耗.与现有的基于代理的多径路由(ABMR)方法相比,LABMP在数据包投递率、能量消耗、额外开销和延迟方面具有更好的性能. 相似文献
6.
Improved video streaming using MSVC and nonoverlapping zone routing multipath propagation over MANETs 下载免费PDF全文
S. Mohideen Badhusha B.G. Geetha Punitha Prabhu R. Vasanthi 《International Journal of Communication Systems》2018,31(10)
Providing real‐time video streaming in mobile ad hoc networks is difficult because of the time‐dependent channel status and stringent service requirements. The currently existing route request‐reply–based multihop overlay networks cause considerable control overheads in video transmission resulting in loss of data and communication breakdown. Such networks are more suitable to nonstreaming video applications rather than to time‐sensitive video streaming applications. Therefore, a powerful mechanism needs to be adopted to handle the channel failures amicably and reduce latency effectively in time critical video streaming applications over mobile ad hoc networks. In order to be resilient to the channel failures and reduce latency in such applications, 2 strategies, namely, multistate video coding and 2‐tier–based nonoverlapping zone routing multipath propagation through directional antennas have respectively been incorporated. The performance of the proposed nonoverlapping zone routing multipath propagation system is compared with those of the existing multicast zone routing and zone‐based hierarchical link state routing protocols with parameters average end‐to‐end delay, routing overhead and packet delivery ratio using NS 2.34. The simulation results show that latency and resilience get considerably improved. Finally, the video quality of the proposed work has been verified by subjective and objective video testing methods. 相似文献
7.
8.
针对由环境复杂性而造成的北斗多路径误差不能有效削弱的问题, 提出了一种基于新的误差模型下的自适应无迹卡
尔曼滤波(UKF)方法。 该方法首先利用量测状态扩增法来解决量测噪声为有色噪声的问题,再用改进的 Sage-Husa 自适应
UKF 来动态估计系统噪声和量测噪声,从而解决噪声统计特性未定造成的误差削弱效果不明显的情况。 实验结果表明在有色
观测噪声下的改进 Sage-Husa 自适应 UKF 算法相比于传统 UKF,能够将多路径误差削弱近 60%,该方法在针对北斗定位中由于
多路径误差产生的噪声不可知的情况具有很强的适用性。 相似文献
9.
For the problem that the localized overload of the integrated networks and the equipment failure will make the business interruption, a virtualized multi path reliable transmission mechanism for the integrated fiber-wireless access networks is proposed. By establishing the virtualized hierarchical model and adopting the centralized management of resources of the virtualized network and the network overall visual superiority, we use the multi-path parallel transmission mechanism to design a recovery scheme after a breakdown so as to ensure the reliable transmission of the network. The results show that the performance of the proposed algorithm is better than the full backup and shared backup algorithm. In addition, the proposed algorithm can ensure the network reliability while the network load balancing is achieved and the resource utilization rate is improved. 相似文献
10.