Mobile Location Estimation in CDMA Cellular Networks by Using Fuzzy Logic

An adaptive fuzzy logic estimator for locating mobiles in a direct sequencecode division multiple access (DS/CDMA) cellular system is proposed. Thelocation estimation is based on the measured pilot signal strengths by themobile station (MS) from a number of nearby base stations (BSs). A smoother,which uses past and current output data from the fuzzy estimator to producea more accurate estimate, is used to improve the accuracy of the locationestimation. Numerical performance results under various path loss and channelshadowing conditions are presented to demonstrate the viability of theproposed fuzzy estimator.     

A survey on communication and data management issues in mobile sensor networks

Wireless sensor networks (WSNs) which is proposed in the late 1990s have received unprecedented attention, because of their exciting potential applications in military, industrial, and civilian areas (e.g., environmental and habitat monitoring). Although WSNs have become more and more prospective in human life with the development of hardware and communication technologies, there are some natural limitations of WSNs (e.g., network connectivity, network lifetime) due to the static network style in WSNs. Moreover, more and more application scenarios require the sensors in WSNs to be mobile rather than static so as to make traditional applications in WSNs become smarter and enable some new applications. All this induce the mobile wireless sensor networks (MWSNs) which can greatly promote the development and application of WSNs. However, to the best of our knowledge, there is not a comprehensive survey about the communication and data management issues in MWSNs. In this paper,focusing on researching the communication issues and data management issues in MWSNs, we discuss different research methods regarding communication and data management in MWSNs and propose some further open research areas in MWSNs.Copyright © 2011 John Wiley & Sons, Ltd.     

Hierarchical location service for wireless sensor networks with mobile sinks

In wireless sensor networks (WSNs), a mobile sink can help eliminate the hotspot effect in the vicinity of the sink, which can balance the traffic load in the network and thus improve the network performance. Location‐based routing is an effective routing paradigm for supporting sink mobility in WSNs with mobile sinks (mWSNs). To support efficient location‐based routing, scalable location service must be provided to advertise the location information of mobile sinks in an mWSN. In this paper, we propose a new hierarchical location service for supporting location‐based routing in mWSNs. The proposed location service divides an mWSN into a grid structure and exploits the characteristics of static sensors and mobile sinks in selecting location servers. It can build, maintain, and update the grid‐spaced network structure via a simple hashing function. To reduce the location update cost, a hierarchy structure is built by choosing a subset of location servers in the network to store the location information of mobile sinks. The simulation results show that the proposed location service can significantly reduce the communication overhead caused by sink mobility while maintaining high routing performance, and scales well in terms of network size and sink number. Copyright © 2009 John Wiley & Sons, Ltd.     

基于移动终端的学校通用固定资产管理系统的设计与实现

文章介绍了基于移动终端的学校通用固定资产管理系统的设计和实现方法。借助该系统,可以帮助从事资产管理的相关工作人员,实现对资产的添加、查询、修改、借还状态、管理等功能,简化原有固定资产管理的繁琐性,改善固定资产使用效率和管理效率,进而提高高校管理水平,为高校数字化、智能化管理添砖加瓦。     

Experimental detection of mobile satellite transmissions with cyclostationary features

One of the important functions of cognitive radio (CR) technology is spectrum sensing. The implementation of an efficient spectrum sensing function can be quite challenging because of various factors such as multi‐path fading, low signal‐to‐noise ratio of the radio communication services to be detected and the requirement to detect and analyze the signal in a short time. As a consequence, it is important to quantitatively assess the performance of spectrum sensing techniques in various scenarios. This paper investigates different digital signal processing techniques for spectrum sensing in the context of mobile satellite transmissions: power sensing, cyclostationary sensing, efficient cyclostationary sensing based on FFT accumulation method and strip spectral correlation algorithm. This paper presents experimental results on the cyclostationary properties of GSM Thuraya mobile satellite communications in various conditions both for the uplink and downlink channels. The receiver operating characteristics are computed, and the results are presented for different algorithms and different positions of the satellite terminals. The experimental results show that the cyclostationary‐feature‐based detection can be robust compared to energy‐based technique for low signal‐to‐noise ratio levels. Copyright © 2014 John Wiley & Sons, Ltd.     

Adaptive delivery of video data over wireless and mobile environments

We present an architecture for the adaptable delivery of video data under variable connection characteristics and into devices of variable capabilities. The main application of the proposed architecture is video delivery in wireless and mobile environments. The architecture is based on the Universal Multimedia Access concept and the MPEG‐7 standard. Based on the network and the mobile device, as well as constraints imposed by user preferences and the multimedia content, video is delivered through a careful application of a combination of off‐line and on‐line reductions to the video stream. We present our architecture and describe an implementation of a system based on the architecture. We present basic performance evaluation results to quantify the merit of our approach. Copyright © 2002 John Wiley & Sons, Ltd.     

基于TEE的移动终端数据安全研究与实现

分析对比了移动终端数据安全的3种实现方式,提出了基于TEE的移动终端数据安全框架,并探讨了典型TEE移动支付方案.在典型方案基础上,创新性地提出了基于TEE的指纹动态调整支付额度的业务方案,最后给出了核心代码实现.     

Attenuation statistics estimated from radar measurements in MEO satellite communication systems for mobile terminals

Based on experimental data, we have reported a method to scale the cumulative time, T_F,T(A), a given attenuation, A (dB), is exceeded in a MEO satellite system in fixed terminals, to the time, T_M,T(A), A is exceeded in mobile terminals. Zigzag routes and ring roads simulated city patterns; straight routes simulated freeways. In all cases, T_M,T(A) can be expressed as T_M,T(A)=ξT_F,T(A) with a probability scaling factor ξ independent of A. Although the satellite systems have been simulated at 19.77 GHz, the results concerning ξ can be considered frequency‐independent. We have used a very large number of rain‐rate maps of storms randomly observed in 1991–1992 by a meteorological radar in Northern Italy. The speed of vehicles was modelled as a lognormal random variable. We found: (a) in zigzag routes T_M,T(A)<T_F,T(A), i.e. ξ<1, with results depending on vehicle speed modelling and starting conditions; (b) in ring roads there is no difference between fixed and mobile systems (ξ≈1); (c) in straight freeways T_M,T(A)?T_F,T(A) (ξ?1) and T_M,T(A) can change significantly in different straight lines and in opposite directions (anisotropy and asymmetry) for medium–large attenuation. When compared with zigzag routes or ring roads, the performance in straight freeways is the most optimistic. The numerical values of ξ applicable to a MEO satellite system are not significantly different from those applicable to a GEO satellite system working in the same conditions. Copyright © 2002 John Wiley & Sons, Ltd.     

移动协助传感器网络中Sink的路径优化策略

在无线传感器网络中引入移动Sink来解决。静态无线传感器网络(所有节点均为静止)存在的能量空洞、冗余覆盖和热点等问题。传感器节点将数据发送给汇聚节点(CP,collection point),移动Sink访问CP节点收集数据。提出了一种最短移动距离最小能耗的路径优化模型(MEMD)。证明了该模型是一个NP-hard问题,给出了一种基于效用的贪心启发式方法用于确定最佳的CP节点队列。为了在规定的最大传输延时的范围内访问尽可能多的CP节点,提出了一种基于CP节点访问概率的路径选择算法。通过模拟实验以及实验床的真实数据,提出的算法能很好地在满足延时要求的同时节约网络的能量。     

DDC-OMDC: Deadline-based data collection using optimal mobile data collectors in Internet of Things

Mobile data collectors (MDCs) are very efficient for data collection in internet of things (IoT) sensor networks. These data collectors collect data at rendezvous points to reduce data collection latency. It is paramount to determine these points in an IoT network to collect data in real time. It is important to consider IoT network characteristics to collect data on a specific deadline. First, the disconnected IoT sensor network is a real challenge in IoT applications. Second, it is essential to determine optimal data collection points (DCPs) and MDCs simultaneously to collect data in real time. In this study, Deadline-based Data Collection using Optimal Mobile Data Collectors (DDC-OMDC) scheme is proposed that aims to collect data in a disconnected network with the optimal number of mobile data collectors in a specific deadline for delay-intolerant applications. DDC-OMDC works in two phases. In the first phase, the optimal number of MDCs is determined to collect data at the optimal data collection points to guarantee one-hop data collection from each cluster. The optimal mobile data collectors are determined using optimal DCPs, data collection stopping time, and a specific deadline. In the second phase, the optimal data collection trajectory is determined for each MDC using the nearest neighbor heuristic algorithm to collect data in real time. The simulation results show that the proposed scheme outperforms in collecting data in real time and determines optimal mobile data collectors and optimal data collection trajectory to collect data in a specific deadline for delay-intolerant applications.     

Multihop data gathering in wireless sensor networks with a mobile sink

Network performance can be improved by using a mobile sink (MS) to collect sensed data in a wireless sensor network. In this paper, we design an efficient trajectory for MS, collecting data from sensor nodes in a multihop fashion, with the aim of prolonging the network lifetime. Considering event‐driven applications, we present an approach to jointly determine the optimal trajectory for MS and data paths and transmission rates from source nodes to MS, without considering any rendezvous points. In these applications, an MS is supposed to harvest the data from source nodes in a given time‐slot. We first show that this problem is in form of a mixed integer nonlinear programming model, which is NP‐hard. Then, to achieve an approximate solution, we divide the mentioned problem into 2 simple subproblems. In fact, after determining an approximate zone for the trajectory of MS, the optimal data paths and transmission rates from source nodes to the MS are obtained through a mathematical optimization model. Finally, to illustrate the efficiency of the proposed approach, we compare the performance of our algorithm to an rendezvous point–based and also the state‐of‐the‐art approach in different scenarios.     

SGDD: self‐managed grid‐based data dissemination protocol for mobile sink in wireless sensor network

The reduction of energy consumption in order to increase network lifetime is one of the most major challenges in the design of wireless sensor networks. During data dissemination, the sensors that are located in the sink's neighborhood are responsible to relay data to the other nodes; hence, their energy is exhausted expeditiously. Therefore, the idea of utilizing mobile sinks can be so advantageous to decrease energy consumption during data dissemination process. In this paper, we propose self‐managed grid‐based data disseminating protocol for mobile sink in wireless sensor networks by using the idea of constructing a virtual grid. In self‐managed grid‐based data disseminating protocol, sink and nodes map their geographical position to a virtual location. In order to increase the performance, we have employed a cell head for each grid cell. Cell heads are selected based on two parameters, centralization and residual energy. Our data dissemination protocol is simple and has low overhead to construct and maintain. Also, we have presented a new method for sink location update, which leads to the least cost in data transfer. Simulation results illustrate that by utilizing hierarchical functionality and determining an optimal size for grid cells, energy consumption is decreased, which leads to increasing network lifetime. Copyright © 2015 John Wiley & Sons, Ltd.     

适用于高数据速率和高速移动环境的多相位匹配信道估计方法

本文给出了多相位匹配信道估计方法，通过这种方法，可以有效地将高维的PSK调制的性能改善到低维的PSK性能，使得在高速移动环境中可以应用高维的PSK调制，因而这是一种适用于高数据速率和高速移动环境的一种有效的信道估计方法。     

利用三星时频差的运动辐射源定位与测速方法

针对高轨三星无源定位系统对空中恒定高度运动目标探测的应用场景,提出了一种利用信号到达时差( TDOA)、到达频率差( FDOA)的无源定位与测速方法。详细描述了算法原理、算法处理步骤,利用STK( Satellite Tool Kit)软件结合计算机仿真,分析了时差测量误差、频差测量误差、高程估计误差对定位精度与测速精度的影响。该方法定位精度与测速精度较高,具有一定的工程应用价值。     

Examination of the data rate obtainable with low‐gain non‐tracking antenna applied to user terminal used for mobile communications and broadcasting services provided by quasi‐zenithal satellites

Link budgets between the mobile user terminal and a feeder link station (2‐m‐diameter antenna) through the quasi‐zenithal satellite system (QZSS) (7‐m‐diameter antenna for Tx, 5‐m‐diameter antenna for Rx) under the power flux density (PFD) limit were calculated for the Ka‐ and Ku‐band. The PFD limit for non‐geostationary satellites is applied for frequency sharing between QZSS and geostationary satellites. The maximum data rate in the Ka‐band was 1.7 times higher than in the Ku‐band in the forward link, while the maximum data rate at Ku‐band is nine times higher than that in the Ka‐band in the return link when the transmit power derived from the regulations of the PFD is applied. And it is more than three times higher than that in the Ka‐band when transmit power is fixed to 2W. In the forward link, maximum data rates are 149 kbps in the Ka‐band and 86 kbps in the Ku‐band when the user terminal antenna is non‐tracking (gain at the satellite direction is 7.1 dBi) and the frequency bandwidth per beam is 30 MHz. Required bandwidth per channel for a certain data rate is large, e.g. in Ka‐band, 20.9 MHz for 64 kbps, 125 MHz for 384 kbps, and 326 MHz for 1 Mbps. In the return link, the maximum data rates are 44 kbps in the Ku‐band and 13.6 kbps in the Ka‐band when the user terminal antenna gain in the satellite direction is 7.1 dBi and transmit power is 2 W. Copyright © 2005 John Wiley & Sons, Ltd.     

移动无线网大数据规划模型研究

随着近年来大数据技术的发展，各行业加强了其在专业领域的研究及应用。对于移动运营商的无线网规划专业，通过结合企业拥有的市场、网络、终端、基站、规划等数据源进行大数据规划将有效提高网络规划的精准度及自动化水平。从目前已有的大数据规划平台来看，一般存在没有充分考虑场景区分及区域类型的问题，这对规划结果有一定影响。首先分析移动无线网大数据规划模型所需数据源、处理应用架构及实施方法，再从移动无线网大数据规划关键环节及模型分析开始分别研究面、线、点 3 种覆盖规划模型包含的标准、算法及参数设置等内容，最后对移动无线网大数据规划模型的构建及应用提出相关思路和建议。     

多功能基站移动终端分组数据业务研究

在GSM多功能基站的基础上增加了实现移动终端分组数据业务的功能,使得多功能基站的功能更加完善,相比于商用基站简化了终端分组数据业务实现的过程且能够在控制端对网络数据的交互进程实施管控。通过对多功能基站的系统参数配置,与终端之间的信令交互,以及对网络层的数据处理之后终端可以在多功能基站下实现分组数据业务,最后在控制终端对网络数据的交互进程进行管控。经过测试证明多功能基站系统能够有效的实现终端分组数据业务。     

基于移动信令数据分析的位置服务与基站定位技术的混合应用

基于移动信令数据分析的位置服务与基站定位是两种不同类型的用户位置服务.一种是即时定位业务,另一种是基于历史信令数据分析的位置业务,二者各有优劣性.提出一些将基站即时定位与基于历史轨迹、区域人群统计的移动信令数据分析位置开放能力相结合的技术方案,并详细描述了这些方案的实现方法.所述内容为电信运营商基于网络信令的位置能力与优化提供了新思路.     

基于数据卸载策略的能量优化方法在移动代理路径规划中的应用

提出了移动代理数据卸载策略,对无线传感器网络中现有移动代理规划路径进行优化,根据卸载规则决定是否将数据分组分离通过优化的卸载路径传递,卸载数据的移动代理通过原路径访问数据源节点.使用移动代理经典算法IEMF(itinerary energy minimum for first-source-selection)进行大量的仿真实验,结果显示,提出的数据卸载策略能有效地解决数据源节点能量消耗过快的问题,延长数据源节点的生存期.