The objective of this project is to develop efficient techniques for reliable video streaming over wireless ad hoc networks. A wireless ad hoc network is a collection of wireless mobile nodes which dynamically form a temporary network without infrastructure. Possible applications of video streaming over ad hoc networks include: a quick set-up for video conferencing in a place without a wireless infrastructure, transmitting video on the battlefield, and search and rescue operations after a disaster. There are many challenges for supporting video traffic over ad hoc networks. Due to the mobility of wireless nodes, the topology of an ad hoc network may change often. Thus the established connection route between a source and a destination is likely to be broken during the period of the transmission, which may cause interruption, pause, or jerkiness in the received video signal. Other factors that influence the quality include random packet loss caused by wireless channel errors and the small capacity of a wireless network.
We propose a cross-layer scheme to address the above problems. In the network layer, the routing protocol will treat video traffic and other traffic differently. It will establish multiple paths between the source node and the destination for video applications to enhance the robustness of the system and increase the bandwidth for an end-to-end connection. When one path is broken during the transmission, the routing protocol can still use other paths to transmit video traffic, and use alternative paths in the middle nodes to rescue the packets that are stuck in the broken path. In the application layer, the agents will monitor the state of the paths and allocate video traffic adaptively.
We will verify our results using both NS simulations and real experiments on an experimental testbed.