Infrastructure vs. Multi-Hop D2D Networks: Availability and Performance Analysis

With the increasing number of wireless networks available, and mobile devices with access to the Internet, it is essential to obtain the best connection, whether this is a direct path through Wi-Fi or cellular or an indirect path via one or multiple peer to peer devices. As an example, multi-hop ad hoc networks are essential in areas where infrastructure networks are unavailable or sparsely available due to natural disasters such as earthquakes, or in conflict or war zone areas. In this paper, we present and analyze the accessibility of WiFi and cellular networks in Rochester, NY, and compare the performance in terms of the upload and download speeds of direct Wi-Fi and cellular connections with 1-hop, 2-hop and a 3hop ad hoc networks based on Wi-Fi Direct. Experimental results show that although Wi-Fi access points are widely available, in more than 20% of locations all of the available access points are inaccessible due to security restrictions. Moreover, the LTE cellular networks provides the highest download speed compared to Wi-Fi and multi-hop Device-to-Device (D2D) networks, while the upload speeds of Wi-Fi and cellular are comparable. Finally, our experimental results show that extending access to the Internet to devices that might not otherwise have a direct connection through multi-hop D2D connections is feasible at the expense of a 62% reduction in upload and 64% reduction in download speed, in the worst case.