Flow Control Technique using U-DTN in Underwater Multimedia Communication and Performance Evaluations

This paper proposes an Underwater Delay/Disruption Tolerant Network (U-DTN) that prevents intermediate nodes from accumulating and losing messages due to the speed gap between different communication media in transmitting and receiving messages, when they communicate more than one hop using communication media in an underwater multimedia communication network. U-DTN proposed in this paper stores messages in auxiliary memory when an intermediate node accumulates messages due to the speed gap in transmission between communication media, reaches the limit of the main memory, and predicts message loss. When the auxiliary memory is full, intermediate node also sends STOP message to its neighbor nodes, sort to pause there message transmission. and than it processes the already-received messages. In the case that it determines that there is no longer a message risk loss, it sends a RESTART message to its neighbors so that it can resume sending messages. In order to investigate the benefits of our flow control technique, we propose mathematical models of the message loss prevention rate and the saving data amount when U-DTN is applied. Moreover, we compare the memory-full time in U-DTN applied case with U-DTN not-applied case to see how much longer (i.e.,benefit time) U-DTN applied case can receive messages with auxiliary memory.