A FRAMEWORK FOR P2P NETWORKING OF SMART DEVICES USING WI-FI DIRECT

ABSTRAC

Increased Persistence of Wi-Fi Direct Networks for Smartphone-based Collision Avoidance

Inter-vehicular communication is a promising technology to improve road safety. Inter-vehicular communication over a wireless medium can be used to exchange important information such as the speed, location, and headings of a vehicle with nearby vehicles. Using this information, it is possible to calculate if a collision is imminent and warn the driver to take action. Wi-Fi can also be used to share this information, however it requires an access point hardware to facilitate communication. Wi-Fi Direct enabled devices can share information without a hardware access point. Wi-Fi Direct provides peer to peer communication by employing a software defined access point embedded within the system. Wi-Fi Direct is a technology that is present on many smart phones, eliminating the need for dedicated access point hardware. In collision avoidance application, Wi-Fi Direct maybe used to exchange safety-related information between vehicles. Collision avoidance systems developed using smartphones can also be extended to protecting pedestrians carrying a smartphone and in this role they could be a long-term solution for certain vulnerable road user collision scenarios. Smartphones with Wi-Fi Direct capability could provide a path to early, low-cost implementation of inter-vehicle communication for collision avoidance. However, there are many limitations to such a system that are addressed in this thesis. Wi-Fi Direct functions by creating groups. One of the nodes in the group is elected as the group owner that acts as an access point and manages the communication between the nodes within the group. If the group owner moves out of range, reforming the group is a lengthy process. This thesis proposes a new method for nomination of the group owner to reduce the likelihood that the group owner will move out of range. This thesis introduces the concept of nominating a Backup Group Owner that can quickly replace the group owner if the group owner shuts down or moves out of range of the group. An orderly handoff from the group owner to the Backup Group Owner can prevent loss of communication among nodes. An analytical study of the amount of time saved by adopting the proposed method of electing the BGO is presented

Content-centric Routing in Wi-Fi Direct Multi-group Networks

The added value of Device-to-Device (D2D) communication amounts to an efficient content discovery mechanism that enables users to steer their requests toward the node most likely to satisfy them. In this paper, we address the implementation of content-centric routing in a D2D architecture for Android devices based on WiFi Direct, a protocol recently standardised by the Wi-Fi Alliance. After discussing the creation of multiple D2D groups, we introduce novel paradigms featuring intra- and inter-group bidirectional communication. We then present the primitives involved in content advertising and requesting among members of the multi-group network. Finally, we evaluate the performance of our architecture in a real testbed involving Android devices in different group configurations. We also compare the results against the ones achievable exploiting Bluetooth technologies

Data Connectivity and Smart Group Formation in Wi-Fi Direct Multi-group Networks

Users of Device-to-Device (D2D) communication need efficient content discovery mechanisms to steer their requests toward the node in their neighborhood that is most likely to satisfy them. The problem is further compounded by the lack of a central coordination entity as well as by the inherent mobility of devices, which leads to volatile topologies. In this paper, we first discuss group-based communication among non-rooted Android devices using Wi-Fi Direct, a protocol recently standardized by the Wi-Fi Alliance. We propose intra- and inter-group communication methodologies, which we validate through a simple testbed where content-centric routing is used. Next, we address the autonomous formation of groups with the goal of achieving efficient device resource utilization as well as full connectivity. Finally, we evaluate the performance of our group formation procedure both in simulation and in a real testbed involving Android devices in different topologies

Wireless ad-hoc networks on Android operating system

Brezžična ad hoc omrežja so omrežja brezžičnih naprav, ki za delovanje ne uporabljajo infrastrukture (dostopovne točke). Naprave, ki tvorijo ad hoc omrežje, so med seboj enakovredne in vse sodelujejo pri usmerjanju podatkov skozi omrežje. Brezžični tehnologiji Bluetooth in Wi-Fi Direct omogočata preprosto izmenjavo podatkov med napravami v dosegu. Zaradi neodvisnosti od infrastrukture lahko Bluetooth in Wi-Fi Direct naprave komunicirajo kjerkoli in kadarkoli. V magistrskem delu smo pregledali možnosti ad hoc povezovanja različnih mobilnih naprav s poudarkom na mobilnem operacijskem sistemu Android. V praktičnem delu naloge smo razvili aplikacijo Android, ki omogoča samodejno povezovanje bližnjih naprav. Za posredovanje podatkov med napravami smo razvili lasten usmerjevalni algoritem, ki v najhitrejšem možnem času poišče najkrajšo pot za prejeti paket podatkov. Vzpostavljeno ad hoc omrežje se prilagaja razmeram s samodejnim povezovanjem. Omenjene so tudi težave in omejitve, na katere smo naleteli pri izdelavi mobilne aplikacije. Te so nastale predvsem zaradi varnostnih zahtev in tehničnih omejitev samih mobilnih naprav in operacijskega sistema.Wireless ad hoc networks are decentralized types of wireless networks which do not rely on infrastructure (such as access points). Devices forming ad hoc networks are equivalent to each other and all participate in the routing process by forwarding data to the other devices. Wireless technologies such as Bluetooth and Wi-Fi Direct allow simple data sharing between devices in reach. Because Bluetooth and Wi-Fi Direct are independent of any infrastructure, devices may communicate anywhere, anytime. This master thesis covers ad hoc connecting possiblities using mobile devices on Android operating system. We developed an Android application that allows automatic ad hoc connecting between mobile devices. For data sharing between devices, we implemented our own routing algorithm that finds the shortest path in the fastest time possible. Established ad hoc network also automatically adapts to any changes. We also mentioned problems and limits that were encountered during the development. Most were a result of a security and technical limits of the mobile devices and operating system