Design And Realization Of Video Monitoring System Based On Wireless Mesh Network

With the development of wireless network technology, there are more and more applications of Wireless Local Area Network (WLAN) technology in our daily life. Wireless Mesh Network (WMN) is new kind of wireless network, originated from the integration of WLAN and Ad Hoc Network, Which can afford higher transmission speed within the more coverage. There are many advantages such as self-organization, self-cure, more flexible and so on than traditional Infrastructure Wireless Networks. Video Monitoring is an effective method of supervision on many different occasions, but there are many weaknesses in the design of wiring and fix physical location and so on in traditional wired network, also lack of enough transmission bandwidth and weak mobility and so on in the wireless network.This paper tries to solve the problems as mentioned above, by presenting a new approach, which combines the WMN and Digit Video Transmission technology. The combination results in some new advantages including getting rid of restrict of wired network, deploying network more flexibly and effectively and extensively, managing and configuring more easily, and remote controlling with the help of network technology. This paper can offer reference about the design video monitoring and of WMN.Firstly, this paper conducts research on WMN's key technology and analyzes Mesh protocol architecture, composed of IEEE 802.11 series of WLAN and Mesh standards. Meanwhile, we get familiar with embedded system development and digital video transmission technologies and master them. Then we choose uClinux operating system and MIPS processor as our target development platform. After accomplishing the WMN's Node (embedded system device), based on which we design video monitoring system.To be more specific, in terms of hardware, we design our development board referring to RT2880 Demo Board produced by Ralink Corp; we adopt pan & tilt as video camera; we adopt Network Video Server (NVS) built-in MPEG4/H.264 encoder as controller, which can adjust the focus and rotation of the camera. In terms of software, we develop driver and application based on uClinux and MIPS platform including the design of bootloader, the porting and construction of kernel image of uClinux, the design of FLASH and wireless card etc, and the design of embedded web server named Goahead. After that, the network is available. We can go to the design of the video monitoring subsystem. The front-end monitoring point cooperated with NVS compress es video, the video data can be received and the camera can be controlled through NVS in the local or remote monitoring center.Lastly, we test the performance of hardware device, and transmission speed and video transmission quality of one-hop and three-hop network. The experiment indicates that the network's performance of high transmission speed and reliability and extensibility can be achieved, and the network can be used in the video monitoring field, and in many other related fields.