introduction
With the rapid development of smart systems and the popularization of smart mobile terminals, in government departments, enterprises and institutions, employees are using smart terminals (including mobile phones and tablet computers) of the Android system for office work. Management is very necessary. Most of the current remote control is based on the application layer. It can only manage and control certain applications or some permissions of the upper layer. It cannot achieve complete control of the Android terminal in a true sense. In addition, these remote controls are only implemented based on a single network and cannot guarantee the stable implementation of remote control.
The control system studied in this paper can use multiple networks for communication, including WiFi, GPRS and GSM. Using the characteristics of the Android bottom layer based on the Linux system, an Agent is built on the bottom layer of Linux to obtain the system signature, and the shell commands that need to obtain root permissions can be executed to achieve complete control of the entire system.
1 Wireless remote control system architecture
A wireless remote control system that communicates based on multiple networks (GPRS, WiFi, GSM), and operates through Linux agents, mainly adapts to various network communication methods, and performs system settings, file systems, and devices for Android smart terminals control.
The basic functions of the system include: automatic registration, sending messages, sending files, managing applications, sending shell commands to control the device, etc.
The wireless remote control system of Android intelligent terminal based on Linux agent is mainly composed of 3 parts: control terminal, controlled terminal and communication network. The architecture of the system is shown in Figure 1.
2 Wireless remote control system design
2. 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 network is fast network speed, but the disadvantage is the requirement of range and signal strength. The advantages and disadvantages of GPRS are the opposite of WiFi wireless networks. At present, the GPRS 2G network transmission rate is around 50 kb / s, and the 3G network is faster. If you use a WiFi network to access the Internet, the speed can even reach 1 Mb / s. The speed can fully meet the rate requirements of the command transmission in the remote control.
This system adopts multi-network mode: WiFi wireless network is preferred, followed by GPRS network, and finally GSM is used to send short message control. When using WiFi wireless network and GPRS network, Android terminals communicate through Socket.
If the system is only used in a local area network, it can only use WiFi wireless network; if it is used in a remote or wide area network, you can use a combination of WiFi wireless network and GPRS network; if there is no WiFi and GPRS, only use GSM The internet.
When used in the WAN, when the controlled terminal finally starts the system, it will use UDP to send the login broadcast to the WAN, or use the TCP protocol to send registration information to the specific control terminal IP. After receiving the information, the control terminal registers with the machine, and then sends control commands via TCP to perform remote control.
In the absence of WiFi and GPRS, you can also use the GSM network to send short message commands for some simple control operations, such as: turning on WiFi, turning on GPRS network, etc., so that they can use the above two networks for control. The prerequisite for using the GSM network is to know the SIM number of the controlled terminal.
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