Title: Characterizing and Mitigating Communication Challenges in Wireless and Mobile Networks

Yang Chen
School of Computer Science
College of Computing
Georgia Institute of Technology

Date: Thursday, October 11th, 2012
Time: 12:00 - 2:00 PM
Location: Klaus 3100

Committee:

• Prof. Mostafa Ammar (College of Computing)
• Prof. Ellen Zegura (College of Computing)
• Prof. Umakishore Ramachandran (College of Computing)
• Prof. George Riley (School of Electrical and Computer Engineering)
• Prof. Jim Xu (College of Computing)

Abstract:
Wireless and Mobile (WAM) networks have been evolving and extending their reaches to more aspects of human activities for years. As such networks have been deployed in wider and boarder physical range and circumstances, end-to-end contemporaneous connectivity is no longer guaranteed. To address this connectivity challenges, recent research work of Disruption Tolerant Network (DTN) paradigm uses intermediate nodes to store data while waiting for transfer opportunities towards the destination. However, these works are distinct from conventional research work in WAM, e.g., MANET routing, since the connectivity assumptions are so different.

In this thesis, we present the WAM Continuum framework which aims to provide a unified treatment of wireless and mobile networks. The framework is based on the construction of a WAM continuum that defines the space of networks and a corresponding formalism by which one can group related WAMs into classes that map into design and operational regimes. We show a specific instantiation of this framework that classifies networks according to their path properties. We extend this framework in a manner that enables the classification of a WAM’s energy “sufficiency” depending on a combination of the network connectivity properties, available energy, and power management scheme. We illustrate our approach by applying it to networks described by traces from both real platforms and mobility models. As another extension under the same WAM continuum framework, this thesis plans to evaluate the interaction of mobile computation implementation and underlying network’s connectivity characteristics.

Classification results from our framework indicate that heterogeneous connectivity may exist in WAM networks. In such cases, protocols from different routing paradigms need to work together to provide effective data communication. We focus on integration of MANET routing and message ferrying in clustered DTNs. A hybrid routing approach is developed in which both MANET routing and message ferrying are used to explore available connectivity in clusters via gateway nodes. Different data aggregation as well as transmission scheduling algorithms are proposed. To achieve better performance, we also study the ferry route design problem in the clustered DTNs and develop three route design algorithms.

This thesis work also includes our experience to address challenges associated with new data communication requirements in oil field operations at remote areas. Backed up by a comprehensive measurement study of long range data links provided by satellite and cellular services, we develop a WAM network where multiple data links are jointly used to achieve an effective data communication solution in the challenged environment.