无线移动网络的协作通信方案研究

结合具体的无线Ad hoc网络,提出了机会性的根据网络实时状况选择最佳中继的协作MAC协议,并在NS-2仿真平台上实现,仿真结果表明,较常规的802.11 DCF协议,协作MAC方案有效地提高了网络的递交率。此外对采用RCPC编码协作的MAC协议进行了数值仿真。这些协议和方案可以直接或修改后应用于现有的Ad hoc等无线网络,在一定程度上可以实现跨层的机会协作通信和组网方案。     

WSN中一种改进的节点部署方案

节点部署是无线传感器网络的基本问题之一,关系到网络的感知范围和信息传输服务质量。现有的部署算法需要额外探测和修复边界上的覆盖空洞,从而增加了网络部署的成本而且使得节点分布不均匀。针对这一问题,提出了一种改进的节点部署方案,首先进行边界部署,以保证边界上的完全覆盖和连通;然后在感应区域内生成一个新的凸多边形区域,在此新区域上再递归调用边界部署算法,直到整个感应区域被完全覆盖。理论分析和仿真实验表明,在部署节点个数和可扩展性方面均优于已有的部署方案。     

无线传感器网络中一种能量有效的簇内通信方案

为了提高簇内通信的能耗均衡性,提出了一种能量有效的分簇无线传感器网络簇内空分通信方案——近簇头节点采用单跳传输,远簇头节点多跳传输,给出了空分通信方案的工程实现。仿真结果验证了空分混合通信方案在能量有效性和能耗均衡分配方面的优势。     

异构无线系统中一种改进的呼叫准入方案

针对异构无线系统中上、下行业务需求不平衡引起的拥塞现象,提出了一种改进的呼叫准入方案。首先给出接入倾向度的概念,在接入时考虑用户的实际接入需求,并进一步提出了基于接入倾向度的呼叫准入改进方案,最后利用无差别曲线的方法确定接入倾向度的选择。仿真结果表明,改进后的方案在系统性能与用户公平性之间做到了较好折衷,具有较大的实用价值。     

无线传感器网络的建模分析

无线传感器网络由大量具有传感、计算和通讯能力的节点组成。针对不同的应用目的、工作环境和要求，提出了进行传感器网络建模需要考虑的几个要素。通过对网络基本要素的描述，能够很方便地对传感器网络进行建模。利用这些要素的特征对网络性能进行深入细致地分析以便选择或设计合适的路由协议和数据融合的方法。研究的重点是网络路由协议及其数据融合技术，也适用于其他协议的设计和建模。     

无线传感器网络的建模分析

无线传感器网络由大量具有传感、计算和通讯能力的节点组成。针对不同的应用目的、工作环境和要求,提出了进行传感器网络建模需要考虑的几个要素。通过对网络基本要素的描述,能够很方便地对传感器网络进行建模。利用这些要素的特征对网络性能进行深入细致地分析以便选择或设计合适的路由协议和数据融合的方法。研究的重点是网络路由协议及其数据融合技术,也适用于其他协议的设计和建模。     

An Enhanced Location‐Based Location Update Scheme in Mobile Cellular Networks

In this study, we consider a location‐based location update (LU) scheme. We propose an enhanced LU (ELU) scheme that can store more cells to reduce the location update cost of the LU scheme and show that the ELU scheme always outperforms the LU scheme. Our scheme can be easily implemented in actual cellular systems.     

A Light Weight Secure Communication Scheme for Wireless Sensor Networks

Wireless Personal Communications - The majority of security systems for wireless sensor networks are based on symmetric encryption. The main open issue for these approaches concerns the...     

An Improved Multifactor User Authentication Scheme for Wireless Sensor Networks

Wireless Personal Communications - Wireless Sensor Networks (WSNs) are used to collect and transmitted the data in various applications from normal to those which requires significant security...     

无线通信网络绿色效率分析

文章首先详细介绍了绿色无线通信技术的产生背景和发展现状,其次系统阐述绿色无线通信的关键技术,最后对无线通信网络绿色效率进行探讨,分析了调制技术同各绿色效率之间的联系,希望对绿色无线通信今后的发展有一定的借鉴意义。     

Hierarchical Group Location Tracking for Transportation Systems in Wireless Personal Communication Networks

A hierarchical group location tracking (HGLT) based on grouplocation tracking and hierarchical location update is proposed toreduce the location management cost for terrestrialtransportation systems (TSs) in personal communication networks. A global group location update (GGLU) and a local group locationupdate (LGLU) are performed to provide an accurate position for auser. The GGLU informs a virtual visitor location register of thecurrently camped-on location area and the LGLU informs the servingmobile switching center of the currently camped-on cell. Althoughthe LGLU is done each time a TS moves into a new cell, it causessmall increment in the signaling cost due to localized updates andgroup updates compared with the previous group location trackingscheme. The proposed scheme significantly reduces the paging costbecause the scheme pages only a camped-on cell using the LGLUinformation. Compared with the previous schemes, the HGLT reducesthe location management cost, and it is more efficient as thecost for paging a cell increases.     

无线自组网在井下语音通信及定位的应用

井下语音通信是煤矿安全系统的组成部分,随着电子通讯技术的发展,已陆续推出几代产品。无线自组织网络技术的自我配置、多跳式无线接力联接、不需要基础通信设施、低功耗和较低的成本等特性正好适应井下无线通信的特点,同时能够增加调度功能,这是传统无线通信系统所不具备的。     

基于802.11e的无线Mesh网络中视频传输优化方案

针对无线Mesh网络环境下视频数据传输的延迟、吞吐量、丢包率等问题,改进了一种数据映射方案,将不同重要程度的数据与IEEE 802.11e中的接入类别相对应,优先发送级别高的数据。对压缩视频数据传输进行了仿真实验,并对仿真结果进行了分析,证明了在不同的网络业务负载下,改进的映射方案对网络性能有一定的改善。     

A Location Management Scheme Using Direction Characteristics of Mobile Terminals in Mobile Communication Networks

Recently, as the number of mobile terminals (or users) keeps explosively increasing, the location management to track the mobile terminals in mobile communication networks is becoming more important. However, previous schemes have used static location information without any consideration about the moving direction of a mobile terminal. For a fixed paging area, this results in unnecessary pagings, thus increasing the location management cost. In this paper, we propose a new location management scheme using the direction characteristics of a mobile terminal. The direction vector is defined to represent the moving direction of a mobile terminal and to compute a distance from the cell where a location update occurs to the current cell. The offset operation of direction vectors is also presented to represent the position of a mobile terminal in a paging area. This allows the mobile terminal to determine whether a location update will be performed or not. The mobile terminal can also vary its own paging area dynamically according to its moving direction whenever it moves across its paging area. In addition, we develop an analytical model for the proposed scheme which captures the direction characteristics of a mobile terminal based on the Markov model. Analytical results show that the proposed scheme can reduce location management cost by forming a dynamic paging area along the moving direction of a mobile terminal when compared to other schemes.Ui-Sung Song received his B.S and M.S. degrees in Computer Science and Engineering from Korea University, Seoul, Korea in 1997 and 1999, respectively. He is currently a Ph.D. candidate in Computer Science and Engineering from Korea University. Also, he is currently a researcher in the Research Institute of Computer Science and Engineering Technology at Korea University. His research interests include mobile IP, PCS networks, and ad-hoc networks.Joon-Min Gil received his B.S. and M.S. degrees in Computer Science from Korea University, Chochiwon, Korea in 1994 and 1996, respectively. He received his Ph.D. degree in Computer Science and Engineering from Korea University, Seoul, Korea in 2000. From 2001 to 2002, he was a visiting research associate in the Department of Computer Science at the University of Illinois at Chicago, U.S.A. He is currently a senior research engineer in Supercomputing Center at Korea Institute of Science & Technology Information, Daejeon, Korea. His recent research interests include distributed and mobile computing, wireless networks, Internet computing, P2P networks, and grid computing.Chong-Sun Hwang received his M.S. degree in Mathematics from Korea University, Seoul, Korea in 1970, and his Ph.D. degree in Statistics and Computer Science from the University of Georgia in 1978. From 1978 to 1980, he was an assistant professor at South Carolina Lander State University. He is currently a full professor in the Department of Computer Science and Engineering at Korea University, Seoul, Korea. Since 2004, he has been a Dean in the College of Information and Communications at Korea University. His research interests include distributed systems,distributed algorithm, and mobile computing systems     

Location Verification Systems in Emerging Wireless Networks

As location-based techniques and applications have become ubiquitous in emerging wireless networks, the verification of location information has become more important. In recent years, there has been an explosion of activity related to lo- cation-verification techniques in wireless networks. In particular, there has been a specific focus on intelligent transport systems because of the mission-critical nature of vehicle location verification. In this paper, we review recent research on wireless location verification related to vehicular networks. We focus on location verification systems that rely on for- mal mathematical classification frameworks and show how many systems are either partially or fully encompassed by such frameworks.     

无线传感网中NLoS环境下的ToA/AoA改进混合定位算法(英文)

An improved hybrid Time of Arrival (ToA)/ Angle of Arrival (AoA) location algorithm by adopting Gauss-Newton iterative algorithm is proposed. It is with the advantage of fast convergence and combining with the grid-search-based method to optimize the initial object coordinates of the iteration, meanwhile, under the condition of small measurement errors caused by noises of ToA and AoA, the algorithm performance can be improved effectively. In the Non-Line-of-Sight (NLoS) environments of the Wireless Sensor N...     

无线传感器网络定位方法的研究

本文对无线传感器网络概念,定位原理,典型定位算法进行阐述,研究几种重要定位技术,对各种算法进行性能分析和比较。     

Wireless Infrared Communication Systems and Networks

International Journal of Wireless Information Networks -     

车辆无线通信网络及其应用

文章介绍了车辆通信网的基本概念、网络架构、国际标准及关键技术,分析了其在物理层、媒体接入层、路由层、安全技术的研究热点问题,并讨论了其在智能交通、安全行车、导航和智能驾驶等方面的应用前景。     

Utilization of Location Information in Cognitive Wireless Networks

Location awareness is an essential characteristic of cognitive radios as well as networks. In this article a location awareness engine architecture is proposed for the realization of location awareness in cognitive radios and networks. The proposed architecture consists of location estimation and/or sensing, seamless positioning and interoperability, statistical learning and tracking, security and privacy, mobility management, and location-based applications. However, the focus of this article is on location-based applications where we demonstrate the utilization of location information in cognitive wireless networks by presenting some representative location-assisted network optimization applications such as location-assisted spectrum management, network planning and expansion, and handover. Our study unveils that location information can be used in cognitive wireless networks to optimize network performance. Possible solutions to the implementation issues are proposed, and the remaining open issues are also addressed.