Research Of Multimedia Transmission And The Simulation Model In DTN

In recent years, multimedia applications gradually penetrate into every field of people's life.P2P file sharing has been widely embraced and becomes the largest application of the Internet traffic. And the development of wireless mobile devices has promoted a trend of deploying Peer-to-Peer (P2P) networks over mobile ad hoc networks (MANETs) for mobile content distribution. Various multimedia content sharing mechanisms in P2P networks over MANET have been proposed in the literatures. However, due to nodes'limited radio transmission range, sparse distribution and nodes'frequent movement, the network is divided and the link is interrupted intermittently. At this movement, MANETs may become Delay Tolerant Network (DTN). Therefore, this paper studies multimedia transmission scheme based on P2P lookup protocol in DTN. Meantime, in order to evaluate the proposed algorithm more truly, this paper proposed a random obstacle-based mobility model (ROM) of the real world.At first, this paper introduces the related knowledge of DTN, P2P and simulation tool ONE. Then for the multimedia transmission on DTN, this paper proposes a Distributed Multisource Parallel Coadjutant Transmission (DMPCT) scheme of multimedia based on P2P lookup protocol. In this scheme, the proposed three mechanisms enable the highest file delivery rate and the lowest transmission delay. That is this scheme can make multimedia files to be sent to the receiver fast and reliably in wireless mobile P2P networks over DTN. In addition, there is no need for a centralized control point. It can resist a certain DoS attack and the senders can freely join and leave from the wireless mobile P2P network without affecting the performance of the algorithm.In order to evaluate the proposed scheme in a realistic mobility model, this paper presents a random obstacle-based mobility model. In this model, the users can place arbitrary-shape obstacles in accordance with any actual scene. The mobile path of a node calculated by this node is the shortest path to the destination avoiding certain types of obstacles. In addition, the propagation model contains the attenuation of the signal due to the existence of obstacles. This paper augments the "Opportunistic Network Environment" (ONE) simulator of DTN with required extensions and shows that the characteristics of the DTN are very different using the new model than it is under models that ONE currently provides. The transmission of multimedia over the wireless networks including ad hoc network and DTN is of great research significance. It can provide technical support for mobile multimedia business. At last, this paper describes the wireless emergency communication network and the emergence of DTN briefly, and then analyzes the possibility of the proposed DMPCT scheme applying to the emergence network.