Architecting Protocols to Enable Mobile Applications in Diverse Wireless Networks

06 Nov
Thursday, 11/06/2008 8:00am to 11:00am
Ph.D. Dissertation Proposal Defense

Aruna Balasubramanian

Computer Science Building, Room 203

The goal of my thesis is to understand the principles underlying the design and implementation of a robust network protocol stack to enable mobile applications in a diverse wireless environment. The primary challenge in enabling applications in the wireless environment is tolerating disruptions. In this thesis, the key insight used for tolerating disruptions is {\em opportunistic resource usage}. I propose three mechanisms for exploiting opportunistic resource usage: {\em Replication, Aggressive prefetching and Opportunistic forwarding}. These mechanisms leverage multiple resources as they become available to tolerate disruptions, but can also increase resource overhead. Therefore, I propose a set of simple, decentralized, utility-driven protocols to implement the three mechanisms in a resource constrained environment. I evaluated the protocols using deployment and trace-driven simulations on two wireless testbeds. The experimental results showed that a wide range of applications including Web search and VoIP can be adapted to the mobile wireless setting using the proposed protocols.

The next challenge I will address is to adapt the protocols to changing network conditions. As the scope and scale of wireless networks grow, a user can be connected to heterogeneous network environments. For instance, as the network connectivity improves, the protocol design should adapt to the improved connectivity to support a wider range of applications. When the network connectivity becomes poor, the protocol should gracefully degrade applications. Similarly, when a mobile user has connectivity to multiple access technologies such as 3G and WiFi, the proposed protocol should simultaneously use the different technologies to improve network access. I propose research required to adapt protocol decisions and design a layering architecture that combines the different protocols into a single stack. The protocol stack will allow a user to seamlessly access applications in diverse network environments.

Advisors: Brian Levine and Arun Venkataramani