基于WI-FI技术的网络电话通信系统的设计与研究

发布时间：2018-02-26 19:22

  本文关键词： WI-FI VoIP网络 MGCP协议 UDP/IP协议　出处：《天津工业大学》2017年硕士论文　论文类型：学位论文

【摘要】：目前,国内大多数石油、化工、煤炭等工矿企业,采用PSTN网络或VoIP网络作为通信系统,这种有线接入方式使得这些工矿企业在环境复杂、施工困难的区域很难铺设电缆,特别是在涉及到工人作业的区域,这一弊端就更为严重;这些工矿企业通常采用独立运行计算机网络、电话通信网络以及程控调度等多种网络系统,致使在网络建设和运行过程中产生大量的设备费、线路费和维修费,增加了企业成本开支;计算机局域网络的最大传输速率可达1000Mbps,在上述企业中,其丰富的带宽资源没有得到充分利用,造成了带宽资源的浪费;同时上述通信系统还存在着呼叫方式单一的缺点,无法实现对不同区域灵活方便的调度。为解决上述问题,本课题提出了基于WI-FI技术的网络电话通信系统的设计,并在对MGCP协议深入研究的基础上,提出精简的O_MGCP协议。O_MGCP协议将RQNT命令嵌入到CRCX命令中并使MDCX命令功能也在CRCX命令中完成;加入SDP协议;支持单呼功能,并在群呼和全呼扩音呼叫时,能够实现扩音呼叫与一般语音通信的灵活切换;省去EPCF命令的设计。本课题硬件设计部分共包括WI-FI电话终端、接入点(AP)、媒体网关控制器(MGC)和中继网关(TG)四个子系统。在各子系统的功能模块中,WI-FI电话终端除了与媒体网关控制器具有相同的主控模块、电源模块、存储单元模块、CPLD模块之外,还具有WI-FI传输模块和MSP430F149单片机键盘扫描及液晶(LCD)显示模块;接入点作为数据转发中心,主要包含WI-FI传输模块和底层驱动模块;中继网关为连接PSTN网络和分组网络,主要由主控模块、中继接口模块、音频译码模块、DTMF转发模块和忙音检测模块组成。软件设计部分包括WI-FI电话终端程序、接入点程序、O_MGCP协议、中继网关程序以及UDP/IP协议。其中在CCS 3.3软件开发平台上,实现了 WI-FI电话终端、O_MGCP协议、中继网关以及UDP/IP协议的程序设计;在Keil4.12平台上,实现了接入点程序的设计;在IAR4.10平台上,实现了 MSP430F149单片机键盘扫描和LCD显示子程序的设计。在Quartus Ⅱ 8.0平台上,采用VHDL语言实现了可编程复杂器件(CPLD)的逻辑控制功能。本课题设计的WI-FI网络电话系统单呼、群呼、全呼三种呼叫方式,还可与PSTN用户通话,具有维护简单、组网便捷以及使用灵活的特点,节省了大量建设电话网络的设备费、线路费和工程费用,并且提高了工矿企业网络资源的利用率,具有显著的经济效益和社会效益。
[Abstract]:At present, most domestic oil, chemical, coal and other industrial and mining enterprises use PSTN network or VoIP network as the communication system. This wired access mode makes it difficult for these industrial and mining enterprises to lay cables in areas where the environment is complex and the construction is difficult. Especially in areas involving workers' work, this disadvantage is even more serious. These industrial and mining enterprises usually use a variety of network systems, such as independent operation of computer networks, telephone communication networks, and program-controlled dispatching. As a result, a large amount of equipment, line and maintenance costs are incurred during the construction and operation of the network, thus increasing the cost of the enterprise. The maximum transmission rate of the computer local area network can reach 1000 Mbps. in the above enterprises, Its rich bandwidth resources have not been fully utilized, resulting in a waste of bandwidth resources. At the same time, the above-mentioned communication system also has the shortcoming of single call mode and can not achieve flexible and convenient scheduling of different regions. This paper puts forward the design of network telephone communication system based on WI-FI technology, and on the basis of deeply studying MGCP protocol, puts forward the simplified OMGCP protocol. OMGCP protocol embeds RQNT command into CRCX command and makes the function of MDCX command complete in CRCX command. Join the SDP protocol, support the single call function, and can realize the flexible switching between the voice call and the general voice communication when the group call and the full call call, and save the design of the EPCF command. The hardware design part of this subject includes the WI-FI telephone terminal, Access Point (AP), Media Gateway Controller (MGC) and Relay Gateway (TGG) are four subsystems. In the functional modules of each subsystem, WI-FI telephone terminal has the same main control module, power module and memory unit module as the media gateway controller, except the CPLD module. It also has WI-FI transmission module, keyboard scanning module of MSP430F149 single chip computer and LCD display module; access point serves as data forwarding center, mainly includes WI-FI transmission module and bottom drive module; relay gateway connects PSTN network and packet network. It is mainly composed of main control module, relay interface module, audio decoding module DTMF forwarding module and busy tone detection module. The software design part includes WI-FI telephone terminal program, access point program and OMGCP protocol. The relay gateway program and UDP/IP protocol are implemented on the CCS 3.3 software development platform, in which the WI-FI telephone terminal, relay gateway and UDP/IP protocol are programmed; on the Keil4.12 platform, the access point program is designed; on the IAR4.10 platform, the access point program is designed. The design of keyboard scan and LCD display subroutine of MSP430F149 single chip microcomputer is realized. On the platform of Quartus 鈪，

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