Ad-hoc communication for mobile devices

Abstract

Nowadays, most networked mobile applications are built following a client-server architecture. In this paradigm, communications between devices are relayed through a centralized infrastructure. This technique has the disadvantage of requiring the presence of a centralized access point and depends entirely on it, which involves network delay and limits mobility. These limitations can be avoided by using an ad hoc model which allows direct communications between mobile devices.

Since ad hoc architecture is less widespread than centralized architecture, fewer resources are proposed for developing ad hoc applications. This master thesis presents the conception and the implementation of a library to facilitate the management of ad hoc networks amongst mobile devices. The library is implemented as a middleware component on the Android platform and is designed according to a layered model where each layer provides specific services. Bluetooth and Wi-Fi Direct technologies are used to establish ad hoc communications. Nevertheless, the main limitation of Wi-Fi Direct is that it does not support multi-hop communications. To overcome this limitation, the library proposes a hybrid approach by using Bluetooth technology to interconnect several Wi-Fi Direct groups. The proposed scheme provides an abstraction layer that handles multi-hop communications independently of the underlying wireless technology and uses the Ad hoc On-demand Distance Vector (AODV) routing protocol. All these mechanisms are encapsulated and are provided as high level APIs to manage ad hoc communications in a convenient way.

Finally, this master thesis provides several proof of concept applications which use the library, a brief performance analysis and gives a conclusion about the work accomplished as well as some suggestions of improvement.