Research On The Massively Distributed Virtual Reality System Design Based On P2P Network

In recent years, according to the development of network technology, the design and achievement of the distributed virtual reality system and the achievement has attracted the reseachers, and has been widely used in various fields. The traditional C/S structure of the Virtual Reality System is limited by the control centre, and the centre server becomes the computing and communication bottlenecks. P2P structure on the establishment of a virtual reality system can avoid the problems of C/S structure effectively. In P2P network, there is not centre manager, and all of the data are distributed on the peers in the system. The core of the distributed virtual reality system design based on the P2P network is researching on the data ditribution and the network topology.Security consistency and real time are the essence requirements of the massively interactive virtual system design. In order to set up a real-time, secure and consistence massively distributed virtual reality system based on P2P network, we unanimously adopted the premise of security, the pursuit of real-time communication as a whole train of thought. We analysis P2P technology and has concluded, to study and explore new design ideas, techniques and methods to resolve challenges in the design of the distributed virtual reality system. There are four aspects of the article:1. Synchronization algorithm for the massively distributed virtual reality system design based on P2P networkSynchronization is the foundation for buiding up a secure and consistent interactive system. We compare the proposed synchronization algorithms. And in accordance with the characteristic of the data in virtual reality system, we select some peers to compute events. The computing peers communicated with each other in conservative synchronization strategy. The entire messages are signatured, then whether the messages are carried out is under supervise. The pipeline mechanism is referenced to improve Response time. The synchronization mechanism is scalable, consistent, safe and real-time.2. Network topology design for the massively distributed virtual reality system design based on P2P networkWe research in the topology of P2P networks for distributed virtual reality system without reliable peers. With fixed visual area of virtual avatar, the corresponding data are also determined. In addition, the targets focused by the peers are changed frequently, leading to the high-frequency of transforming interactive group. This paper propose the concept of "Cell" as the elementary units to assignment of computation, and a virtual world hierarchical model, called Cell Model, where peer can locate the computation and communication objects by itself. Reasonable assignment of computation make sure the correctness and security of computation and communication. There is a computing multi-overlay network when all the peers follow the partition arrangements, which implements the inter-surveillance to avoid the one-peer cheats. This paper analyze the computation load of Cell model by experiment, compare the communication of Cell Model with traditional model, and the results shows the reliability of system is increased and the load of communication is decreased in Cell Model.Through the establishment of discrete space index peer topology Cell model, to reduce the frequency and reduce the network to find application layer routing Jump step effect. And in their self-organization established on the basis of group interaction, a reasonable calculation of the distribution, so as to achieve in ensuring the security and real-time, under the premise of reducing the total amount of computation system results. In addition, the system is robust, the system in each peer to district units for the storage and backup, unless the community to participate in the same terms and concerns of all peer failure, it will certainly be a system restore.3. Peer assessment algorithm for the massively distributed virtual reality system design based on P2P networkWith the topology of the virtual reality system, the peers are divided into computing peers and getting update peers. Due to the diversity of network, the state of peers will change continually. Reputation is a good idea for judging the credibility of peers. In this paper, the credibility of peers is quantitied based on the synchronous communication state. We proposed the local reputation for selecting computing peers to adjust the load balance of computation and communication of the system.4. Application layer multicast algorithm for the massively distributed virtual reality system design based on P2P networkInteractive network with small world model will produce clusters of peers in the high density areas. The peers with the same source download data at the same time, that will bring the large burden to the source peer. The topology needs reasonable adjustments, to ensure system stability. Getting update peers get new state from the computing peers. According to the increase of interaction group, the number of computing peers as source is reduced comparatively. The burden of bandwidth increases. We introduced the application layer multicast for the design of distributed virtual reality system. Analysing the existing application layer multicast algorithms, we proposed a multi-source multicast algorithm for Cell model. Based on the assessment of the peers, the topology is adjusted in two ways: adjustment within a single tree and adjustment between trees. Experiment proved that the algorithm to adapt topology to reduce communication delays under the network bandwidth constraints.