introduction
With the rapid development of intelligent systems and the popularity of intelligent mobile terminals, in government departments and enterprises, employees use Android-based smart terminals (including mobile phones and tablets) to work more and more, using the network to control mobile terminals and Management is very necessary. The current remote control is mostly based on the application layer. It can only manage and control certain applications or some upper-level permissions. It cannot achieve complete control of the Android terminal. In addition, these remote controls are based on a single network implementation and do not guarantee stable implementation of remote control.
The control system studied in this paper can communicate using a variety of networks, including WiFi, GPRS and GSM networks. Based on the characteristics of the Linux system based on the implementation of the Linux system, an agent is built on the underlying layer of Linux to obtain the system signature, and the shell command that needs to obtain the root authority can be executed to achieve complete control of the entire system.
1 Wireless remote control system architecture
Wireless remote control system based on multi-network (GPRS, WiFi, GSM) communication and operation through Linux agent, mainly adapts to various network communication methods, and performs system setting, file system and equipment for Android intelligent terminal. control.
The basic functions of the system include: automatic registration, sending messages, sending files, managing applications, sending shell commands to control devices, and so on.
The Android remote terminal wireless remote control system based on Linux agent is mainly composed of three parts: the control terminal, the controlled terminal and the communication network. The architecture diagram of the system is shown in Figure 1.
2 wireless remote control system design
2.1 Multi-network communication design
The networks currently supported by Android smart terminals are: GPRS wireless network and WiFi wireless network. The advantage of WiFi wireless networks is that the speed of the network is fast, and the disadvantage is the range and signal strength requirements. The advantages and disadvantages of GPRS and the WiFi wireless network are just the opposite. At present, the transmission rate of GPRS 2G network is about 50 kb/s, and the speed of 3G network is faster. If the WiFi network is used to access the Internet, the speed can reach 1 Mb/s. The speed requirement for transmitting commands in remote control can be fully achieved at speed.
The system adopts multi-network mode: the WiFi wireless network is preferred, the GPRS network is used secondly, and the short message control is adopted by GSM. When using WiFi wireless network and GPRS network, Android terminals communicate through Socket.
If the system is only used in the LAN, you can only use the WiFi wireless network; if the application is on the remote or wide area network, you can use the combination of WiFi wireless network and GPRS network; if there is no WiFi and GPRS, use GSM The internet.
When used in the WAN, when the system is controlled to start the system, the UDP method is used to send the login broadcast to the WAN, or the TCP protocol is used to send the registration information to the specific control IP. After receiving the information, the control terminal registers with the local machine and then sends a control command via TCP to perform remote control.
In the absence of WiFi and GPRS, the GSM network can also be used to send short message commands for some simple control operations, such as turning on WiFi, turning on the GPRS network, etc., so that it can be controlled using the above two networks. The prerequisite for using a GSM network is that it is necessary to know the SIM number of the controlled terminal.
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