Reliable Transmission of Video over Ad-hocNetworksUsing Automatic Repeat Request and

Abstract-The increase in the bandwidth of the wireless chan-nels and the computing power of the mobile devices makes it possible to offer video service for wireless networks in the near future. In an ad-hoc network, strong error protection is required because of the lack of fixed infrastructure. On the other hand, the mesh structure of an ad-hoc network implies that there may be multiple paths existing between a source and destination, which can be used to enhance video transmissions. In this paper we propose a simple but robust scheme for reliable transmission of video in bandwidth limited ad-hoc networks. In our scheme, a video stream is layer coded. The Base Layer (BL) packets and the Enhancement Layer (EL) packets are trans-mitted separately on two disjoint paths using Multi-path Transport (MPT). BL packets are protected by Automatic Repeat Request (ARQ), and a lost BL packet is retransmitted through the path where EL packets are transmitted. An EL packet has lower priority than a retransmitted BL packet and may be dropped at the sender when congestion occurs. Simulation results show that this scheme can guarantee a graceful video quality in ad-verse channel conditions. It is effective for video transmission over the high loss environment found in ad-hoc networks