A Novel Approach for Sharing White Board Between PC and PDAs with Multi-users

White board sharing between PC and PDAs is a typical interactive application between PC and mobile device in ubiquitous environment. Due to the limited size of PDA’ s screen, when a large amount of clients simultaneously use PDAs to share the server’s screen while their viewed areas (or viewports) are different in size and position, the server must transform the viewports to fit the size of PDA for each client and thus will suffer from heavy burden. A novel approach is proposed in this paper to reduce the burden of the server and provide the clients with real time white board sharing. Instead of zooming the viewport to fit PDA’s screen for every user, it only zooms the screen nine times; then, chunked encoding is adopted to reduce the cost for encoding the overlapped area of different viewports. The experiment results have demonstrated the efficiency and effectiveness of our approach.