File Sharing In Wireless Local Area Network With Reliable Broadcast Support

File sharing as one of the most effective ways in people’s work and study, has been recognized by many people. In order to facilitate the daily life, many scholars have realized file sharing in mobile terminal. But for some scenes in real environment, the common file sharing system can’t meet the needs of users. For example, when the network situation is not good or even no network, users cannot share files. Or in the user-intensive environment, when multiple users simultaneously request the server to obtain the same file, it is easy to cause the network congestion. Now we need a new file-sharing ways to meet the needs of users in the above scenario.This paper proposed a file sharing system-- FileShare, it implemented on the mobile terminal. In this system, users can organize into a network for file sharing by themselves without taking into account the external environment of the network. If multiple users request the server, the system will choose a node as a representative node to obtain files from the server, then this node organizes network and broadcasts the file data in the network, so that all nodes are available to the file.The FileShare uses ad hoc network in network layer. Using UDP broadcast in the network, can make each node to complete file sharing quickly. However, the UDP broadcast is unreliable and cannot guarantee the recipient to receive the complete file. In this paper, a reliable broadcast mechanism is proposed for the above problems. When the receiver considers that packets are lost in the network, it will inform the sender through the feedback mechanism. After receiving feedback information, the sender makes the appropriate treatment and then sends the packet again until all of the nodes are no longer sending feedback information, the sender considers that all nodes have received files. This feedback mechanism ensure the reliability of broadcast to some extent.After realizing the function of file sharing in WLAN, this paper adds the server node to this system. Through the combination of Seafile and my own file sharing system, this paper realizes the function that the nodes in WLAN can share files with the server.Finally, the file sharing experiment in WLAN proves that the increase of the number of nodes in the network will not result in the performance of the system decreasing. The file sharing experiment between terminal nodes and server confirmed that nodes which cannot be connected to the server can share files with server, and this system greatly improves the efficiency of file sharing when comparing with the situation that each node should connect to the server to get the file.