Efficient data dissemination for Wi-Fi peer-to-peer networks by unicasting among Wi-Fi P2P groups

Recently, the Wi-Fi peer-to-peer (Wi-Fi P2P) technology is discussed to be able to support communications in infrastructure-less network scenarios. In many of such application scenarios, disseminating data (or information) to all network devices is an important issue. According to the Wi-Fi P2P specification, a device can communicate with other devices after joining a Wi-Fi P2P group. A Wi-Fi P2P group is a star network (rooted at a group owner). The group owner can disseminate data to all network devices by broadcasting. However, the Wi-Fi P2P broadcasting mechanism cannot guarantee successful delivery of packets. In order to disseminate data reliably, a possible solution is to disseminate packets to network devices by unicasting. But, by this manner, the group owner will run out of its energy quickly and the time needed to disseminate data to network devices will be lengthened. To consider the above factors, in this paper, we formally define a Wi-Fi P2P data dissemination (WPDD) problem, and prove that this problem is NP-complete. Instead of using one Wi-Fi P2P group to connect all network devices, we propose to divide devices into multiple groups. We then propose a tree-based dissemination scheme and a ring-based data dissemination scheme to achieve data dissemination among groups. The proposed schemes can be compatible with the Wi-Fi P2P specification. We evaluate the performance and effectiveness of the proposed schemes by simulation programs and prototyping implementations.