Development And Application Of Conversion Interface Between Ethernet And Mobile Communications Network

The construction of large scientific instrument working status monitoring system is one of the important projects of national science and technology foundation condition platform construction. By constructing the large scientific instrument working status monitoring system, we can effectively monitor the use of the large scientific instrument and provide technical support for the effective management of the large scientific instrument of the country, thus to improve the utilization of the large scientific instrument.This study make a further research in how to enrich the communication mode between the bottom recorder and the upper server of the large scientific instrument condition monitoring system and how to solve the problems in the network transmission of the present monitor system. This study puts forward a new type of network structure which uses local Ethernet in local short distance data transmission and Mobile Communication Network in external long-distance data transmission, and develops the network transformation interface based on embedded internet technology and GPRS / SMS Short message network technology. The network transformation interfaces can realize mutual transformation between Ethernet data package and Mobile Communication Network data package, and it effectively solves the problem of the transmission of time data between software recorder and hardware recorder under special network environment. This study has made research mainly in the following aspects:1. Making the overall design of the network transformation interface according to the demand of the remote monitoring system of the scientific instrumentThis part firstly analysis the need on the research of the network transformation interfaces, and we found the following problems in many monitor systems and data collecting systems on the network transmission at present: Installing Ethernet in special condition; remote data transmission of the computer terminal forbidden from connecting to the internet; the reliability decrease of data transmission caused by the delay of the Ethernet. Moreover, we confirmed the development target of the system according to these problems, and put forward the overall design project of the system development. The core thought of the project is recovering the different format data to the original data, and realize the communication between data when it is in its original status.2. Realization of the simplification of TCP/IP protocol and the access to Ethernet based on 8-bit MCULarge scientific instrument working status monitoring system requests its interior network equipment to have the characteristics of low cost, low power loss, steady performance, etc. Owing to these characteristics, we select the plan of "8-bit MCU + network card chip + TCP/IP protocol stack" for the network transformation interface to realize embedded internet technology. Owing to hardware resources of the 8-bit MCU are limited, we must simplify the TCP/IP protocol stack. The simplified protocol stack only retains IEEE802.3, ARP protocol (Address Resolution Protocol), Ping protocol of ICMP protocol (Internet Control Messages Protocol), IP protocol (Internet Protocol) and the TCP protocol (Transmission Control Protocol).We reduce the size of TCP/IP protocol stack effectively, and realize the development of embedded internet technology based on 8-bit MCU. On the basis of the key technology, we also complete the development of network transformation interface Ethernet module.3. The development of network communication module based on SMS short message and GPRS technologyOwing to the characteristic of the SMS short message and GPRS technology, SMS short message can be applied to the network environment which has small amount of data transmission, high reliability and the high security of the computer to monitor, at the same time, GPRS can be applied to the network environment which has small amount of data transmission, high requirements of real-time and the low security of the computer to monitor. This study chooses the Wavecom Corporation's Q2406 wireless CPU as the interface of the Mobile Communication Network in the hardware design. In the software development, it mainly solves how to use the MCU to control the Q2406 to realize SMS short message business and GPRS business, and also explains the information which returned by the SMS and GPRS.4. Accomplishment of the device development and test of the entire systemThis study completes development of the system data processing modules and the external auxiliary modules, and develops a complete network transformation interface sample with the integration of the front two parts. It tests each function of the system in the network environment which is not easy to transmit data by Ethernet. Comparing to the traditional transmission by the Ethernet, the performance of the network transmission interface is better in special condition, and it can be applied to the large scientific instrument working status monitoring system.The work that needs to be further carried out:(1) Because that the short news data wrapped in the sky the network(MS arrive BSS) didn't adopt any encryption, hence there exists security issue, and we must encrypt the sky connection part of the SMS short news with A5, in order to change the condition of transmitting SMS data package by way of clear statement form; The mainly security issue of the GPRS system lie in that the encryption of GPRS system is from the ambulation platform to the SGSN, but not port to port. As for the application that need encryption from port to port, we have to consider this factor. We can't depend on the safety of the GPRS system only, but also to add security function at the time of system designing.(2) Increase the function of long range maintenance:most parts of network conversions interface apply in regions which is far from the general server, and once the software system goes wrong or needs to be upgraded, much effort and material is needed for on-the-spot maintenance. If we add the function of long range maintenance to the system, we can login the software system of the network transformation interface through Internet, and carry out the maintenance and upgrade for it.