1. University of Pennsylvania Department of Electrical and Systems Engineering ABSTRACT: The Sensor Application System for PDAs allows users to take advantage of the 802.11 ad hoc mode to transfer files with neighboring users. The advantage of an ad hoc network is that there is no need for an access point. Instead users can connect to each other anywhere, even those locations where internet infrastructure isn’t already setup. For this project there are essentially three components: the physical communication system, the network programming, and the PDA application. The application is created for the Pocket PC 2002 Operating System. It detects other users of the Sensor application in a 100 m range and loads records of their shared files in a SQL server database. The user then has the ability to choose and download any of these shared files from any other user connected to the Ad-hoc Network. AUTHORS : Mohammad Haq CTE ’05 Hamad Abdulaal CTE ’05 ADVISORS : Dr. Saleem Kassam Dr Matthew Blaze DEMO TIMES : Thursday, April 21 th, 2005 1PM to 3PM GROUP 18 Design Approach: There are three components to our system: The networking system, the database, and the application. The first step was modeling the Ad hoc network and how it was going to operate. Then a P2P file sharing model had to be constructed. Then based on these models, a Pocket PC 2002 application developed on Visual Studios. NET connects to the network layer for communication and also connects to a SQL Server Database where all the records are stored. Design Diagram Ad hoc Network Structure Broadcast Ping Request to all users in Ad hoc Network Receive Ping Response from Users in Range Update Database of Sensor Users Request List of Shared Files & Sizes from Sensor Users Receive Text File Containing all Shared Files from all Users Update Database of Shared Files User Searches Database for File User Sends Request to User with Desired File DATABASE OF USERS DATABASE OF SHARED FILES Establish Connection with User with Desired File Transfer File into Shared Folder Application Interface Ad hoc and P2P: There is a distinct difference between the Ad hoc network and the P2P network. The users of the P2P network are a subset of the users of the Ad hoc network. The P2P users are determined by those users who are connected using the Sensor Application. The application acts as both a network client and a network server on the P2P network. Every 15 seconds, the Sensor application refreshes the user and shared file databases to keep network content updated. After a user selects a file, a direct connection is setup through FTP. The desired file is transferred from the other user into the shared folder. Application Interface: Like any traditional file sharing program, there will be 3 main pages. The first page offers the user various options such as selecting the shared folder, disabling uploads, and selecting a user name. The second page is the Search Page which allows users to search for files in the database. Users can search by filename, username, file type, and media type. A list of search results are listed just below the search box and a list of the users connected to the P2P network are shown on the right. Clicking on a user’s name will display that user’s shared files. The final page is the Transfer Page where all the current file downloads and uploads are displayed. For each file being transferred, there is information about the files size, the transfer rate, and the progress. Start PageSearch PageTransfers Page Layer-Based Application Diagram P2P Flow Chart