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1.
针对无线传感器网络(WSN)中单一通过RSSI估计距离的算法易受环境影响产生误差,提出了一种基于RSSI和LQI的分段距离估计改进算法。首先分析了RSSI算法特点,然后在距离估计过程中引入了链路质量,根据预设范围调整定位算法,从而降低RSSI距离估计算法的误差,提高了距离估计精度。实验结果表明,基于RSSI和LQI的分段距离估计改进算法的距离估计精度与原算法相比有了明显提高。  相似文献   

2.
设计了基于森林监测的传感网功能结构和基于ZigBee/802.15.4标准的森林监测传感网体系结构。根据森林监测的特点,设计了基于CC2520和低功耗的MSP430F5437处理器的节点以及结合ARM处理器和协调器的控制节点,从物理层上实现了能量控制。利用基于ZigBee/802.15.4标准无线传感器网络节点,对无线电传播路径损耗模型以及CC2520的分析,用分段线性逼近的方法得到发送功率与RSSI、LQI及节点间距离的关系。通过进一步优化得到发送功率与片码错误率、节点间距离的关系,建立了一种适合在通信开销小、硬件要求低的场合下使用的基于节点间距离、接收信号强度指示和链路质量指示的跨层功率控制算法。  相似文献   

3.
突发性链路感知的自适应链路质量估计方法   总被引:1,自引:0,他引:1  
提出了一种无线传感器网络中突发性链路感知的自适应链路质量估计方法 EasiLQE。节点周期性地发送控制分组,采用长周期主动探测机制探测链路的质量;同时,节点被动侦听接收到分组的RSSI均值,当低于某一阈值时,触发短周期链路质量探测过程。最后节点使用基于误差的滤波器估计链路在未来一段时间内的质量。实验结果表明,EasiLQE既能实时准确地感知突发性链路在短时间内的持续变化,又能平滑短暂的低幅度波动而保持良好的稳定性,同时维持较低的估计开销。  相似文献   

4.
介绍了进行短波地空通信链路计算的主要参数,探讨了对短波地空通信系统进行性能评估的主要方法,并利用ITS软件进行短波地空链路仿真并得出结果.结果可显示到地理图上,协助拟定频率规划方案,并可得出相应的电磁性能.  相似文献   

5.
徐帆  邹玲 《中国新通信》2013,(14):35-37
无线网络,是利用无线电波作为信息传输的媒介构成的无线局域网。随着无线通信改变人们生活方式的同时,人们对无线网络链路质量的要求越来越高,因而大量研究人员对无线链路质量测量问题展开了深入的研究。现有的研究中衡量无线链路质量指标有多种,本文采用通过MATLAB对这些指标进行分析,进行无线网络链路质量的评估分析,主要是针对无线链路质量测量的方法进行整理及对比,通过对无线链路质量指标的测量分析来评估质量的好坏。  相似文献   

6.
引言信号接收器系统的设计师常常需要进行系统性能的级联链路分析(从天线一直到ADC)。在链路分析中,噪声是一个至关重要的参数,它限制了接收器的总体灵敏度。对系统拓扑结构来说更加重要,原因是拓扑结构的选择力求优化总体信噪比、动态范围和诸多其它参数。噪声计算中的一个问题是需要在链路中各组件(即电路的RF、IF/基带和ADC部分)所使用的不同噪声单  相似文献   

7.
提出一种基于LQI置信度的三维空间定位求精算法(3D-RABLC)。通过大量节点实验,获得节点间一跳RSSI值与距离的关系、LQI与分组错误率的关系,依此划分LQI置信度,对测得的RSSI值进行过滤,建立三维多跳求精模型或弥补求精方法对置信度低的RSSI值进行修正。节点实验表明,该算法大大降低了RSSI测距误差,比已有三维定位算法具有更好的定位精度。  相似文献   

8.
针对室内白光可见光通信系统基本集中在直射链路的研究时忽视了漫射链路实际应用价值的问题,通过建立一个封闭的实验空间环境,设计可见光通信实验系统,测量漫反射信号的空间分布规律,探索漫反射信号在实际环境中应用的可行性,并进行了基于漫反射的白光可见光通信实验。实验结果表明:漫反射为可见光通信直射链路中阻塞、阴影所导致的信号中断以及室内角落通信质量差等问题提供了解决途径。  相似文献   

9.
针对卫星链路通信性能问题,从影响卫星通信的主要因素入手进行分析,主要论述了天线增益与天线效率给卫星链路通信性能造成的影响。天线增益与天线效率影响着卫星链路通信的质量与效率,因此加强其影响研究,有着现实的意义。  相似文献   

10.
超短波通信链路分析   总被引:8,自引:0,他引:8  
主要从通信系统设计的角度出发,对超短波通信链路分析进行了初步探索,介绍了能量传播分析法和链路余量分析法以及多径条件下的考虑。结合工程实践,给出了超短波通信链路分析示例,这将有助于系统工程师预知系统设计性能、控制技术风险、进一步提高信道估值的可信度。  相似文献   

11.
In the application of Wireless sensor net-works (WSNs), effective estimation for link quality is a basic issue in guarantying reliable data transmission and upper network protocol performance. A link quality es-timation mechanism is proposed, which is based on Sup-port vector machine (SVM) with multi-class classification. Under the analysis of the wireless link characteristics, two physical parameters of communication, Receive sig-nal strength indicator (RSSI) and Link quality indicator (LQI), are chosen as estimation parameters. The link qual-ity is divided into five levels according to Packet recep-tion rate (PRR). A link quality estimation model based on SVM with decision tree is established. The model is built on kernel functions of radial basis and polynomial re-spectively, in which RSSI, LQI are the input parameters. The experimental results show that the model is reason-able. Compared with the recent published link quality es-timation models, our model can estimate the current link quality accurately with a relative small number of probe packets, so that it costs less energy consumption than the one caused by sending a large number of probe packets. So this model which is high efficiency and energy saving can prolong the network life.  相似文献   

12.
Location of wireless sensor nodes is an important piece of information for many applications. There are many algorithms present in literature based on Received Signal Strength (RSSI) to estimate the location. However the radio signal propagation is easily influenced by diffraction, reflection and scattering. Therefore algorithms purely based on RSSI may not accurately predict the position of the node. In the present work, an algorithm for estimating the position of mobile nodes is proposed which is based on a combination of Received Signal Strength (RSSI) and Link Quality Indicator (LQI). Artificial Neural Networks are used to establish the relationship between the location of the mobile node and the experimentally obtained values of RSSI and LQI. Two different algorithms namely, Bayesian Regularization and Gradient Descent are used to develop the neural network model. Proposed algorithms improve the localization accuracy and perform better than other state-of-the-art algorithms.  相似文献   

13.
The personal access communication system (PACS) radio interface is the leading low-tier candidate for standardization in North America. This radio interface was originally conceived to serve pedestrian and fixed-distribution applications; there has been significant recent interest in extending this technology into high-mobility environments. In such environments, rapid channel variations significantly degrade the performance of the preselection diversity scheme proposed for use in PACS handsets. The effects of time-delay spread on the PACS radio link was also included in our investigation. It is found that a received signal strength indicator (RSSI) with a short measurement length can better cope with high fading rates than can a quality measure in a preselection diversity system, although a quality measure has better performance than RSSI at low speeds in the presence of time-delay spread. In the preselection diversity scheme, using short-measurement RSSI provides relatively good performance in both low- and high-mobility environments. However, its performance degrades rapidly for RMS delay spreads larger than about 9% of a symbol time. Postselection diversity using two complete receiver chains is more robust than preselection diversity, both to high fading rates and to delay spread. Postselection diversity is relatively insensitive to changes in the fading rate and can tolerate an RMS delay spread up to 12.5% of a symbol time  相似文献   

14.
局部无线定位系统中的高精度定位算法研究   总被引:1,自引:1,他引:0  
局部无线定位技术是基于局部组网的低成本和低复杂度的定位技术。在局部无线定位中,无论采用哪种技术,都会受到非视距和多径传输的影响,给定位带来较大的误差。环境建模可以通过曲线拟合的方式来建立某些典型场景的信号传输模型。除此之外,在前期环境建模完善的条件下,进一步提高精度只能依靠监控端软件中几何定位算法的改进。文章提出了一种...  相似文献   

15.
随着信息技术的发展,人们对复杂的室内环境下的定位与导航的需求日益增大。文中实现了一种基于LQI的低成本、实用的无线传感器定位系统,系统包括硬件平台、节点通信程序和上位机监测软件三部分。硬件平台以集成了射频与ARM7微控制器的MC1322X芯片为核心,包括射频模块、辅助电路、功能指示电路等。节点软件的开发以FreeScale公司提供的BeeStack协议栈为基础,文中同时给出了节点的软件实现方案。  相似文献   

16.
朱黎  谭建军  黄双林  胡涛  徐鹏飞 《电讯技术》2017,57(9):1071-1076
针对ZigBee网络与WiFi网络共享2.4 GHz频段造成的信道干扰问题,提出了一种基于线性调频再扩频技术的ZigBee网络中WiFi干扰避免方法.该方法根据检测接收数据包中的链路质量指示值计算ZigBee网络链路通信质量,将链路通信质量作为判断WiFi网络干扰强弱的依据:当链路通信质量低于最低容忍阈值时,利用线性调频再扩频技术展宽ZigBee网络信道射频信号频谱,反之则保持原有射频信号频谱带宽传输数据.Matlab仿真结果表明,该方法能明显提升ZigBee网络抗击WiFi信号干扰的能力,具有较好的实际应用价值.  相似文献   

17.

Indoor localization using a Received Signal Strength Indicator (namely, RSSI localization) has been considered a poor measurement for target tracking. The main cause of this inaccurate measurement is that RSSI’s behaviors heavily depend on environmental factors. That is, one significant challenge to localization using RSSI is that the strength of a signal varies with the environment confounding wireless communications power and signal control. In this paper, we propose Circular RSSI And Multi-Sector tracking (CRAMStrack), a novel approach to reducing the uncertainty of RSSI localization by modifying the relationship of RSSI-to-Distance (RtD), based on the sectors of a circle and the position of the tracked target. Traditional RSSI tracking uses one uniform RtD relationship to locate a target whereas CRAMStrack utilizes multiple RtD responses for each wireless sensor. The paper examines CRAMStrack’s tracking ability in a Euclidean space with estimation techniques. Real-world experiments demonstrate CRAMStrack in a testbed environment to locate targets in both stationary, linear, and non-linear movement patterns with single and group-based formations. The track accuracy was about 1.46m for moving targets, while CRAMStrack had a 40% reduction in Root Mean Square Error (RMSE) over Uni-RtD using neighboring sensor information.

  相似文献   

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