The Design And Implementation Of Wireless Multimedia Sensor Networks

Wireless multimedia sensor networks(WMSNs) can be widely used in battlefield reconnaissance and surveillance, intelligent home networks, environmental and agricultural monitoring, etc. Therefore, the research and implementation of WMSNs have important theoretical and practical significance.After analyzing characteristics and key technologies of WMSNs, we firstly design the hardware platform architecture of a node in a WMSN based on the functional requirements Basically, the node contains a Xscale processor and an embedded Linux operating system. Furthermore, we study the implementation of routing protocol AODV over the embedded Linux and multimedia technology including the video capture process based on V4L, the H.264encoding and RTP real-time transport protocol. Eventually, a testbed of the wireless multimedia sensor network with five nodes is built, which has laid the technical foundation for the further research and development of WMSNs.For hardware platform design of a sensor node, firstly we proposes a scheme containing an embedded processor and a video capture chip after comparing and analyzing the several typical hardware solutions of a multimedia sensor node. Based on this, a hardware platform containing mainly peripherals such as USB wireless network card and USB camera is implemented. For the software design of a sensor node, the protocol stack is given after the analysis of functions and characteristics of each network protocol layer. Then, Linux is selected as the operating system of s sensor node by comparing several typical embedded operating systems.The following is the implementation in detail of WMSNs. Firstly, the wireless multimedia sensor network node is built including the establishment of embedded development environment, the configuration and transplantation of bootloader, the pruning of embedded Linux kernel and the producing of root file system. Then, the implementation of a wireless network interface and wireless routing protocol are elaborated, which include the Driver transplantation of USB wireless network card and the implementation mechanism and transplant process of AODV routing protocol in the Linux kernel. Finally, we design and implement the multimedia application program including the the video capture process based on V4L, video coding program based on H.264and its optimization on the Xscale processor, real-time transmission program based on RTP/RTCP protocol.At last, we tested and analyzed the routing functions and the QoS performance of the WMSN established. Then, we demonstrated the video monitoring application over. The results show that AODV protocol can function routing on the WMSNs and the network performance can meet the basic demand for real-time multimedia monitoring.