分类：设计开发    下载：0    浏览：342    时间：2017-07-29

摘要 IEEE802.11b( 研究表明! 只要重叠或相邻C11 小区中心频率相距%E2/0 以上! 就可以有效避免同频或邻频干扰" 在C11 小区密集地区! 需要严格的频率规划" 提出并实现适用于IEEE802.11b( 的一种抗干扰自适应频率规划机制" 测试表明! 在无严格频率规划条件下! 该机制能抗同频或邻频干扰和其它窄带信号干扰改善性能" 关键词:WLAN  抗干扰自适应频率规划

分类：设计开发    下载：2    浏览：570    时间：2017-07-29

刘军, 郭伟, 肖百龙, 黄飞 ( 电子科技大学通信抗干扰技术国家级重点实验室, 四川成都610054) 摘要: 通过分析IEEE 802. 11 DCF 的分组发送过程, 获得了RTS 和基本方式下分组传输的时间开销。给出了以最小化传输时间开销代价为优化目标的最优RTS 门限的计算公式。通过对当前信道分组发送的成功概率Ps 的预测, 实现了最优RTS 门限的计算, 并给出了一个具体的自适应RTS 门限调整算法, 使终端能自动调整其RTS 门限以达到或接近最优值。仿真表明自适应RTS 门限调整算法有效减小了MAC 分组传送的时间开销, 提高了信道的传输效率。 关键词: 无线局域网; 802. 11 DCF; RTS 门限; 分组成功传送概率; 自适应RTS 门限调整

分类：设计开发    下载：0    浏览：552    时间：2017-07-29

初建朋，李小进，赖宗声 (华东师范大学微电子电路与系统研究所，上海 200062) 摘 要：分析了802.11a无线局域网(WLAN)OFDM基带接收系统中频率同步和信道估计算法的运算特点。针对实际算法的特点，设计了一个面向应用的专用DSP处理器(ASP)，利用ASP可以以软件方式实现802.11a前导序列的接收。经实际流片验证表明，该设计可以实现11a前导序列接收的各种基带处理运算，具有高度的灵活性和较小的芯片面积。 关键词：正交频分复用；软件无线电；面向应用数字信号处理器；软硬件协同设计；无线局域网 Analysis and ASP Realization of 802.11a Frequency Sync. and Channel Est. CHU Jianpeng, LI Xiaojin, LAI Zongsheng (Institute of Microelectronics Circuit & System, East China Normal University, Shanghai 200062) 【Abstract】This paper analyzes the calculation cost and characteristics of 802.11a preamble receiving. Realization of these algorithms using SDR,which is based on an application specific DSP and S/W codesign, is introduced. An effectively DSP processor architecture is designed. The testresults show this design is able to implement 11a baseband process effectively and flexibly. 【Key words】OFDM; SDR; ASP; SW/HW codesign; WLAN

分类：设计开发    下载：0    浏览：589    时间：2017-07-29

3GPP网络同WLAN互连方案分析

分类：设计开发    下载：0    浏览：515    时间：2017-07-29

王春东1,2，王秀峰1 (1. 南开大学信息科学技术学院，天津 300071；2. 天津理工大学计算机科学与工程系，天津 300191) 摘要：研究了在基于802.11的系统中，如何通过信号强度进行移动设备的室内定位。在研究并实现最大群中心定位算法MCCPA的基础之上，给出了一种利用移动终端的历史位置信息对定位结果进行修正的室内定位算法(MMCCPA)。其主要思想是，在给定前一时间使用者所在位置的条件下，将使用者出现在特定范围的概率列入考量加以修正，并作为对环境因素影响的调整，这样不仅减少计算量，而且明显提高了位置估算的正确率。 关键词：无线网络；信号强度；定位算法；802.11；历史记录 Research on 802.11-based Indoor Positioning Algorithm WANG Chundong1,2, WANG Xiufeng1 (1. College of Information Science Technology, Nankai University, Tianjin 300071; 2. Dept. of Computer Science & Engineering, Tianjin University of Technology, Tianjin 300191) 【Abstract】This paper focuses on how to position the mobile device indoor by using signal strength in 802.11-based system. It introduces a802.11-based positioning system called the maximal cluster centered positioning algorithm (MCCPA). The MCCP system locates mobile objects viacollecting the sensed power strengths of the mobile objects to multiple wireless access points. Based on realizing MCCPA, the paper gives a newalgorithm named MMCCPA to correct the positioning results by using the history record information of mobile devices. The main idea of MMCCPAis that it also considers the probability of users’ appearance in the specific area in order to correct results, as an adjustment to the environmentfactors, so as to increase the preciseness and decrease the count quantity.The experimental results show that the location information provided byMMCCPA assures higher correctness than MCCPA. 【Key words】Wireless networks; Signal strength; Positioning algorithm; 802.11; History record

分类：设计开发    下载：0    浏览：501    时间：2017-07-29

李骐，陈 涤 (山东大学信息科学与工程学院，济南 250100) 摘 要：研究了实时多媒体业务传输协议在无线－有线混合网络中所面临的新问题，在此基础上提出了一种基于TCP友好速率控制协议的新的实时业务的流控机制，利用延迟抖动率作为丢包分辨信号来调整TFRC的速率控制，以区分拥塞丢包和无线信道丢包。大量的NS仿真实验表明：该算法在无线－有线混合网络中能提高有效通过量，对于TCP流具有良好的公平性。 关键词：无线－有线混合网络；TCP友好速率控制；延迟抖动率；NS-2 TCP-friendly Rate Control Algorithm Based on Wireless-wired Hybrid Network LI Qi, CHEN Di (School of Information Science and Engineering, Shandong University, Jinan 250100) 【Abstract】Real time multimedia transport protocols in wireless-wired hybrid network are facing new challenges. On the basis of extensive studyof characteristics of wireless-wired hybrid network and the current TFRC mechanism, this paper proposes a new TCP-friendly rate controlmechanism for real-time traffics. The new mechanism uses Jitter ratio as the signal to differentiate congestion losses and wireless link losses to adjustTFRC’s rate control algorithm. Extensive simulations on NS-2 verify that the new mechanism has better performance than TFRC as well as keepsreasonable friendliness to TCP flows. 【Key words】Wireless-wired hybrid network; TCP-friendly rate control (TFRC); Jitter ratio; NS-2

分类：设计开发    下载：0    浏览：826    时间：2017-07-29

明 亮1,2，谢桂海1，齐子元1，王新锋1，彭德云1 (1. 军械工程学院计算机工程系，石家庄 050003；2. 北京系统工程研究所，北京 100101) 摘 要：提出了基于无线网的视频智能监控系统的原理结构、带宽适应性和智能监控的实现方法，描述了系统中使用的无线组网、基于SPIHT视频编解码算法和基于内容的视频识别等关键技术，给出了系统实现后的实际测试结果及相关性能指标。 关键词：无线网；智能监控；网络视频；流媒体 WLAN-based Remote Video Intelligent Surveillance System MING Liang1,2, XIE Guihai1, QI Ziyuan1, WANG Xinfeng1, PENG Deyun1 (1. Department of Computer Engineering, Ordnance Engineering College, Shijiazhuang 050003; 2. Beijing Institute of System Eengineering, Beijing 100101) 【Abstract】This paper introduces a video intelligent surveillance system, and presents the structure of the system, adaptability for bandwidth andthe method for intelligent surveillance. It describes the key technologies, such as WLAN, efficient video coding arithmetic based on SPIHT(setpartition in hierarchical trees), intelligent alarm aroused by video-recognizing, and so on, gives out the testing results and important parameter ofperformance by realizing the system. 【Key words】WLAN; Intelligent surveillance; Network video; Streaming media

分类：设计开发    下载：0    浏览：487    时间：2017-07-29

赵 玲，黄生叶 （湖南大学计算机与通信学院，长沙 410082） 摘要：针对移动网络中新的增值数据业务的增加、性能指标多样化的现状，提出了一种具有共享缓存、支持可变比特率业务的接入网系统模型，给出了性能参数的计算方法、兼顾分组层性能参数(丢包率和平均时延)和连接层性能参数的CAC算法，数值计算结果表明了该方法的正确性。 关键词：新用户呼损率；切换用户呼损率；丢包率；平均时延；服务质量；无线网络 Call Admission Control Strategy for Wireless Network Based on Shared Buffer ZHAO Ling, HUANG Shengye (College of Computer and Communication, Hunan University, Changsha 410082) 【Abstract】As more and more value-added data services are devoloped which require complex quality of service(QoS), this paper defines awireless access network model with shared buffer and derives mathematical expressions for some QoS parameters. It proposes a jointCACalgorithm considering both packet-level QoS and connection-level QoS. The numerical results proves correctness of the method. 【Key words】New call block probability; Handoff call block probability; Packet loss probability; Average delay; QoS; Wireless network

分类：设计开发    下载：0    浏览：584    时间：2017-07-29

宋亚楠1，仲茜2 (1. 大连理工大学电子与信息工程学院，大连 116023；2. 清华大学计算机系，北京 100084) 摘要：针对传统报警系统存在直观性差、虚警率高和不易安装等问题，设计了一种新型的无线视频报警系统，给出了软硬件解决方案。该系统结合了MMS的嵌入式技术、无线网络通信技术和多媒体技术，克服了传统报警系统所存在的缺陷，提高了报警的及时性和准确性。目前此系统已投入实际应用。 关键词：MMS；嵌入式；视频报警系统 Embedded Wireless Video Alarm System Based on MMS SONG Yanan1, ZHONG Qian2 (1. School of Electronic and Information Engineering, Dalian University of Technology, Dalian 116023; 2. Department of Computer Science and Technology, Tsinghua University, Beijing 100084) 【Abstract】This paper introduces a new type alarm system and gives its novel S & W solution of embedded wireless video alarm system based onMMS for straightening up the shortcoming of the traditional alarm system, which resultsin that the local video can't obtain in time and the fault rateof alarm of system is very high. This system integrates the embedded technology, advanced wireless network communication technology, and themultimedia technology. It implements transmitting real-time video with MMS, making the alarm information more timely and exact. This system hasbeen put into application. 【Key words】MMS; Embedded; Video alarm system

分类：设计开发    下载：0    浏览：457    时间：2017-07-29

程浩，史杏荣 (中国科学技术大学电子工程与信息科学系信息处理中心，合肥 230027) 摘要：研究了从无线到有线网的基于IEEE802.11e和DiffServ(区分服务)的端到端的QoS结构，介绍了802.11e、802.1D/Q和DiffServ的特点，并就它们之间的优先级映射进行了分析，从流量分类、标记、整形方面对IEEE802.11e和DiffServ的QoS参数提出了分级的接口。 关键词：无线局域网；802.11e；DiffServ；QoS End-to-End QoS Architecture Based on IEEE802.11e and DiffServ CHENG Hao, SHI Xingrong (Information Processing Center, Department of Electronic Engineering and Information Science, University of Science and Technology of China, Hefei 230027) 【Abstract】This paper studies an end to end QoS architecture between wireless and wire based on DiffServ and IEEE802.11e, introduces thecharacters of 802.11e, 802.1D/Q and DiffServ, analyzes priorities mapping each other and presents the hierarchical QoS parameters interfacebetween DiffServ and 802.11e in terms of traffic classifying, markering and shaping. 【Key words】WLAN; 802.11e; DiffServ; QoS

分类：设计开发    下载：2    浏览：571    时间：2017-07-29

王 军1,2,3，王宏1，徐皑冬1，周侗1 （1. 中国科学院沈阳自动化研究所，沈阳 110016；2. 中国科学院研究生院，北京 100039； 3. 沈阳化工学院计算机科学与技术学院，沈阳 110142） 摘 要：EPA是我国第一个拥有自主知识产权的现场总线标准，现已正式成为IEC的PAS文件。作者在参与开发出“基于无线局域网的EPA网络控制系统”的相关设备后，分析和探讨了为适应不同需要的EPA若干无线与有线网段集成的方案。同时，提出了一种符合EPA标准的无线现场总线设备结构的实现模型。从而为实现了EPA进一步向无线工业现场总线进军提供了一定的理论基础。 关键词：EPA；集成模式；无线现场总线 Research of Integrated Wired/Wireless Fieldbus on EPA WANG Jun1,2,3, WANG Hong1, XU Aidong1, ZHOU Tong1 (1.Shenyang Institute of Automation, Chinese Academy of Sciences, Shenyang 110016; 2. Graduate School, Chinese Academy of Sciences, Beijing 100039; 3. School of Computer Science & Technology, Shenyang Institute of Chemical Technology, Shenyang 110142) 【Abstract】The EPA profile that is the first industry Ethernet profile of China is constituted. It has been a PAS in IEC. After the authordevelopedequipment of EPA network control system on WLAN, the paper analyses and expatiates some methods for an integrated hybrid(wired/wireless) EPAfieldbus to adapt to different conditions, and provides a model of wireless fieldbus equipment framework on EPA. It provides some theoryfoundation for EPA occupying more market on wireless fieldbus. 【Key words】EPA; Integration mode; Wireless fieldbus

分类：设计开发    下载：2    浏览：590    时间：2017-07-29

王春东1,2，王秀峰1 (1. 南开大学信息科学技术学院，天津 300071；2. 天津理工大学计算机科学与工程系，天津 300191) 摘要：研究了在基于802.11的系统中，如何通过信号强度进行移动设备的室内定位。在研究并实现最大群中心定位算法MCCPA的基础之上，给出了一种利用移动终端的历史位置信息对定位结果进行修正的室内定位算法(MMCCPA)。其主要思想是，在给定前一时间使用者所在位置的条件下，将使用者出现在特定范围的概率列入考量加以修正，并作为对环境因素影响的调整，这样不仅减少计算量，而且明显提高了位置估算的正确率。 关键词：无线网络；信号强度；定位算法；802.11；历史记录 Research on 802.11-based Indoor Positioning Algorithm WANG Chundong1,2, WANG Xiufeng1 (1. College of Information Science Technology, Nankai University, Tianjin 300071; 2. Dept. of Computer Science & Engineering, Tianjin University of Technology, Tianjin 300191) 【Abstract】This paper focuses on how to position the mobile device indoor by using signal strength in 802.11-based system. It introduces a802.11-based positioning system called the maximal cluster centered positioning algorithm (MCCPA). The MCCP system locates mobile objects viacollecting the sensed power strengths of the mobile objects to multiple wireless access points. Based on realizing MCCPA, the paper gives a newalgorithm named MMCCPA to correct the positioning results by using the history record information of mobile devices. The main idea of MMCCPAis that it also considers the probability of users’ appearance in the specific area in order to correct results, as an adjustment to the environmentfactors, so as to increase the preciseness and decrease the count quantity.The experimental results show that the location information provided byMMCCPA assures higher correctness than MCCPA. 【Key words】Wireless networks; Signal strength; Positioning algorithm; 802.11; History record