基于WLAN的VoIP语音通信终端组呼及设备控制研究

发布时间：2018-01-22 00:13

本文关键词： WLAN VoIP H.323 SIP WinCE操作系统 DCF EDCF　出处：《北京交通大学》2016年硕士论文　论文类型：学位论文

【摘要】：随着计算机网络技术的飞速发展和大数据时代的到来,人们越来越重视信息交流的实时性和跨地域性,而以互联网为载体的多媒体语音通信业务正成为时下的研究热点。VoWLAN(Voice over WLAN)是一个结合了VoIP(Voice over IP)和WLAN(无线局域网)的新的发展方向,它涵盖了无线通信技术、计算机网络技术和嵌入式系统化开发等多个领域的前沿科学。VoIP通过网络传输语音信号,WLAN使终端设备通过无线接入点进行上网,这两者的有机结合可以利用现有的WLAN网络实现无线VoIP通话能力,这样在节约通信成本的同时又提高了网络资源的使用效率。本课题主要目标是设计并实现一款基于WLAN的VoIP语音通信终端设备,利用现有的WLAN网络实现VoIP语音无线通话功能,用户可以通过VoIP语音终端设备在WLAN网络覆盖范围内随时进行语音业务的注册、呼叫、挂断和应答等基本操作；同时针对现场的工业级应用,开发了更加具有针对性的组呼和设备控制特色功能；其次,基于NS2网络仿真平台,研究适用于本终端的MAC层随机接入协议,保障语音业务在整个WLAN数据、语音、视频业务中的服务质量(QoS)；最后通过仿真模拟和实际测试验证VoIP语音终端基本功能和组呼、设备控制功能的有效性和可靠性。本文首先介绍课题的研究背景及意义、课题的国内外研究状况和研究目标,分别阐述WLAN和VoIP的基本概况并对VoIP两大体系协议SIP和H.323做了对比分析,随后对本文的核心协议SIP从功能、特征等方面进行了详细的理论介绍；其次,本文进行了VoIP语音终端的总体设计,包括系统的设计目标和设计原则以及软硬件平台环境,其中对VoIP语音终端的硬件设计主要包括核心处理器模块、存储器模块,电源、音频、JTAG等外围模块,软件设计主要包括SIP协议栈oSIP的基本功能模块：解析器模块、状态机模块和工具模块,VoIP语音终端核心模块：语音处理模块、数据传输模块、组呼功能模块、设备控制模块和用户交互模块,以及应用程序的代码分析和实现方法；再次,对WLAN的MAC层接入机制DCF、EDCF进行了理论介绍并模拟系统网络架构完成了QoS性能仿真,仿真结果表明EDCF机制在网络负载逐渐增大的情况下可以提供更好的QoS；最后,搭建了基本测试环境,对VoIP语音终端的核心功能：注册、呼叫、挂断、应答、组呼和设备控制进行了有效性和稳定性测试。
[Abstract]:With the rapid development of computer network technology and the arrival of big data era, people pay more and more attention to real-time and cross-regional information exchange. And the multimedia voice communication service based on the Internet is becoming the research hotspot. VoWLAN Voice over WLAN is a combination of VoIP (. Voice over IP) and WLAN (wireless local area network) new development direction. It covers the wireless communication technology, computer network technology and embedded systematic development and other areas of the forefront of science. VoIP over the network to transmit voice signals. WLAN enables terminal devices to access the Internet through wireless access points. The combination of the two can make use of the existing WLAN network to achieve wireless VoIP communication capability. This saves the cost of communication and improves the efficiency of network resources. The main goal of this project is to design and implement a VoIP voice communication terminal equipment based on WLAN. Using the existing WLAN network to realize the VoIP voice wireless call function, the user can register and call voice services at any time through the VoIP voice terminal equipment in the WLAN network coverage area. Basic operations such as hanging up and answering; At the same time, aiming at the industrial application in the field, a more targeted function of group call and equipment control is developed. Secondly, based on the NS2 network simulation platform, the MAC layer random access protocol which is suitable for this terminal is studied to ensure the QoS of voice service in the whole WLAN data, voice and video service. Finally, the effectiveness and reliability of the basic function of VoIP voice terminal and the function of group call and equipment control are verified by simulation and actual test. Firstly, the research background and significance of this paper are introduced. The domestic and foreign research status and research objectives of the topic, respectively, the basic situation of WLAN and VoIP, and VoIP two major system protocols SIP and H.323 are compared and analyzed. Then, the paper introduces the core protocol SIP in detail from the aspects of function, feature and so on. Secondly, this paper carries on the overall design of VoIP voice terminal, including the design goal and design principle of the system, as well as the software and hardware platform environment. The hardware design of VoIP voice terminal mainly includes the core processor module, memory module, power supply, audio JTAG and other peripheral modules. The software design mainly includes the basic function modules of SIP protocol stack oSIP: parser module, state machine module and tool module VoIP voice terminal core module: voice processing module, data transmission module. A group call function module, a device control module and a user interaction module, as well as a code analysis and implementation method of the application program; Thirdly, the MAC layer access mechanism of WLAN is introduced theoretically and the QoS performance simulation is completed by simulating the system network architecture. Simulation results show that the EDCF mechanism can provide better QoS when the network load increases gradually. Finally, the basic test environment is built, and the effectiveness and stability of the core functions of VoIP voice terminal, such as registration, call, hang up, response, group call and equipment control, are tested.
【学位授予单位】：北京交通大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TN916.5;TN925.93

【相似文献】