| Natural disaster occurred frequently in China.When major disasters such as earthquakes,floods,and mudslides occur,the fixed communication infrastructure is often severely damaged,which leave the communication network in the disaster area paralyzed.The communications between the front-line disaster relief personnel are difficult,and it is difficult to transmit the real-time disaster situation back to the command center for disaster relief quickly,which seriously hinders the disaster relief work.For example,when the Wenchuan Earthquake struck,the mobile communication base station was destroyed,and it took China mobile nearly 147 hours to restore the communication service to normal.However,the World Health Organization pointed out that the prime time for earthquake relief is only 72 hours.When a disaster occurs,how to quickly deploy a flexible and robust communication and monitoring network in the disaster area is obviously of great significance to the rescue of the victims.This paper focus on the design and prototype development of wireless ad hoc network communication and monitoring system for disaster relief.The system consists of portable wireless ad hoc network terminals and a command center monitoring platform.When a disaster occurs,the relief personnel carry the wireless ad hoc network terminal into the disaster area.After the terminal is powered on,it can quickly build a multi-hop,flexible,and robust communication network based on the self-organizing network protocols without any fixed infrastructure.It can support the transmission of video,voice,file and text among disaster relief personnel,and provide guarantee for the disaster relief work.At the same time,any portable terminal can be designated as a monitoring gateway to access the Internet.The command center monitoring platform can access the portable terminal of any disaster relief personnel through the gateway,and get the real-time situation of the disaster area through the monitoring system to provide support for the command decision-making of disaster relief.Based on the above design philosophy,we have completed the development,manufacturing and testing of the system prototype.The following are our main contributions:(1)Design and implement the hardware and application software of portable terminal.By adopting Samsung Exynos4412 processor,we design and construct the system hardware platform,which provides various on-board resources,including power module,USB module,WiFi network card,audio and video module,CPLD screen display module,etc.Based on Qt framework,we develop multi-function touch operation interface for the portable terminal to support the collection and transmission of multimedia services,such as video,voice,text,files and images.The interface is friendly and convenient for user to operate.(2)Design and implement an IP-based,multi-hop and self-organizing dynamic routing protocol.The physical layer and data link layer of the portable terminal adopt a standard WiFi network card.To realize the multi-hop ad hoc networks for portable terminals,we adopt the fundamental principles of dynamic source routing protocol(DSR)to implement the IP-based multi-hop dynamic routing protocol in the TCP/IP protocol stack of embedded Linux operating system.The experiment results demonstrate the effectiveness of the protocol to fulfillment the process of on-demand route discovery and route maintenance.(3)Design and implement the command center monitoring platform.In this paper,the command center monitoring platform based on Web is designed and implemented by using HTML and JavaScript language.If any portable terminal is set as a monitoring gateway and connected to the Internet,the remaining terminals can be connected to the gateway by means of multi-hop self-organization and finally connected to the Internet.Disaster relief personnel can access the any one of the portable terminals through the monitoring platform and get the real-time situation of the disaster.The experimental results prove the effectiveness of the platform. |
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