基于eXosip协议的软电话研究与设计

目前SIP协议在VOIP中的应用越来越广泛,许多VOIP系统都采用SIP作为它们的信令通信协议,在实现VOIP系统的过程中对于SIP协议栈的选择及应用就显得非常重要。本文设计一种软电话,利用EXOSIP协议来进行信令交互,只要在同一网内,就可以不受限制的进行通话

无线Mesh网络网关负载均衡研究综述

无线MESH网络是无线局域网和移动自组织网络相结合的产物,作为一种能够提供高带宽网络接入服务的全新架构的网络,无线MESH网络目前越来越多的得到人们的重视。本文对近年来MESH网络网关节点负载均衡的研究方向进行了归纳总结,并提出了自己的设想和方向

LTE小区间干扰协调技术研究

本文对lTE系统小区间干扰进行讨论,分析干扰产生的原因,介绍了现有的干扰协调技术,并提出一种资源优先级调度的lTE干扰协调技术

基于SIP的B2BUA服务器设计

SESSIOn InITIATIOn PrOTOCOl(SIP)是下一代网络的核心控制协议,用于在IP数据网络上建立、改变和结束多媒体会话。SIP服务器作为下一代网络的核心设备,它的实现就显得尤为重要。一种方法是代理服务器PrOXy,它只在SIP交互时保存状态,而不是在整个呼叫中维护状态,这限制了代理服务器更大范围的应用。另一种方法是背对背的用户代理(b2buA,bACk-TO-bACk uSEr AgEnT)服务器,它在整个呼叫过程中都维护状态。文章从SIP协议的基本原理出发,利用rESIPrOCATE协议栈实现SIPb2buA服务器并对其做了压力测试

基于Android的SIP远程视频监控系统的设计

本文利用SIP协议建立组呼来控制监控摄像头,从而建立多路远程视频监控系统。论文介绍了基于AndrOId系统的SIP协议栈JAIn-SIP和远程视频监控系统架构,阐述了利用SIP扩展消息完成组呼控制,从而实现监控中心对远端监控摄像头的呼叫控制

Cross-Layer Handover Scheme for Multimedia Communications in Next GenerationWireless Networks

ROC NSC [97-2221-230 E-018-020-MY3, 98-2218-E-151-004-MY3]In order to achieve seamless handover for real-time applications in the IP Multimedia Subsystem (IMS) of next generation network, a multiprotocol combined handover mechanism is proposed in this paper. We combine SIP (Session Initiation Protocol), FMIP (Fast Mobile IPv6 Protocol), and MIH (Media Independent Handover) protocols by cross-layer design and optimize those protocols' signaling flows to improve the performance of vertical handover. Theoretical analysis and simulation results illustrate that our proposed mechanism performs better than the original SIP and MIH combined handover mechanism in terms of service interruption time and packet loss

Web server design of the embedded system based on Android

随着InTErnET技术的兴起,在嵌入式设备的管理与交互中,基于WEb方式的应用成为目前的主流。本文主要论述了基于AndrOId系统环境,在家庭网关中实现嵌入式WEb服务器的设计方法,介绍了I-JETTy嵌入式WEb服务器,及其WEb应用功能的实现。By the internet technology rising,the application of Web becomes the mainstream in the management and interactive for embedded devices.The paper mainly presents a design method which implements the embedded Web server based on Android.A kind of embedded Web server called i-jerry and the realization of the web application function are introduced厦门市科技计划项目资助(3502Z20113005); 厦门大学大学生创新创业训练计划资助(0630-ZX11A1

GSM系统级仿真的初步架构与思考

文章首先简要介绍系统级仿真平台架构,然后详细讲解了公共信道覆盖仿真模块和业务信道仿真模块,最后对仿真结果进行了分析,结果表明采用蒙特卡罗仿真,对现网的参数优化有一定的指导作用

A technique for autonomous structural damage detection with smart wireless sensor network

In this paper, a distributed structural damage detection approach is proposed for large size structures under limited input and output measurements. A large size structure is decomposed into small size substructures based on its finite element formulation. Interaction effect between adjacent substructures is considered as 'additional unknown inputs' to each substructure. By sequentially utilizing the extended Kalman estimator for the extended state vector and the least squares estimation for the unmeasured inputs, the approach can not only estimate the 'additional unknown inputs' based on their formulations but also identify structural dynamic parameters, such as the stiffness and damping of each substructure. Local structural damage in the large size structure can be detected by tracking the changes in the identified values of structural dynamic parameters at element level, e. g., the degrading of stiffness parameters. Numerical example of detecting structural local damages in a large-size plane truss bridge illustrates the efficiency of the proposed approach. A new smart wireless sensor network is developed by the authors to combine with the proposed approach for autonomous structural damage detection of large size structures. The distributed structural damage detection approach can be embedded into the smart wireless sensor network based on its two-level cluster-tree topology architecture and the distributed computation capacity of each cluster head