Mobile Computing Group Research Directions
We envision highly flexible environments of heterogeneous wireless networks of devices with different capabilities that have access to multiple channels or network interfaces and roam over different networks. In general, such environments are extremely complex and the interaction of different layers and technologies creates many situations that cannot be foreseen during the design and testing stages of technology development. This is especially true for wireless networks, which are used for many different purposes, and which are based on a shared medium that is inherently more vulnerable than its wired counterpart. It is therefore critical to perform comprehensive empirical studies in a wide range of production environments to uncover deficiencies and identify possible optimizations and extensions.
The availability of high-quality measurement and modeling studies would make it possible to develop wireless networks that are more robust, easier to manage and scale, and able to utilize scarce resources more efficiently. Our ultimate technological goal is to develop intelligent and robust wireless network, which can be defined as network of devices that in a self-organizing manner, monitor the environment, analyze its performance, and adapt based on their resources and what was learnt to increase their quality of service. The two essential components of this technology are (a) efficient, accurate and scalable measurement and analysis techniques, and (b) adaptation mechanisms that can optimize the performance and robustness of the entire system under real workloads. The underlying philosophy in our research efforts is to tightly integrate these two components by performing extensive real-life wireless measurements, analysis, and modeling, and designing well-founded adaptation mechanisms. We will demonstrate the main principles of our approach in the design of capacity planning, load balancing, device adaptation, and location-sensing algorithms.
Our research work uses real measurement data collected from large-scale wireless networks. A significant part of the measured data is available to the research community via the joint UNC/FORTH repository of traces and models for wireless networks
.Motivated by the intermittent connectivity that mobile users experience, I have been investigating mechanisms to increase their data availability. In 1998, I proposed a novel system, which I realized in my Ph.D. thesis, introducing a new research direction in mobile information access. Its emphasis is at the edge of the network on the application layer rather than on routing protocols or on infrastructure-based approaches. It addresses the challenge of increasing data availability by providing a novel mechanism that enables wireless devices to share resources. The focus is on three facets of cooperation, namely information sharing, network connection sharing and message forwarding.
Peers communicate via a (wireless) LAN and some of them have (intermittent) connection to the Internet (e.g., using Bluetooth or a modem or a base station). In the information sharing facet, peers query, discover and disseminate information. When the network connection sharing is enabled, the system allows a host to act as an application-based gateway and share its connection to the Internet. For message relaying, hosts forward messages to the Internet (when they gain Internet access) on behalf of other hosts.
We designed, prototyped and evaluated 7DS, an architecture and set of protocols, that enables this resource sharing in a self-organizing, peer-to-peer fashion without the need of an infrastructure. The system adapts its communication behavior (e.g., query frequency, type of cooperation) based on the availability of power and bandwidth and privacy constraints.
We have been integrating 7DS with other applications (note sharing, web browser, travel guide); 7DS act as the underling information discovery tool for these applications.
We also explored the use of the mobile peer-to-peer paradigm in location sensing.
For more information (including downloadable software), visit the 7DS webpages.