The demand for wireless services has experienced explosive growth in recent years with no signs of abatement. Much of the remaining potential gains in wireless communications inherently require the synergy of both theoretical and experimental methods. The objective of this project is to achieve significant gains in wireless system performance and spectral efficiency through a tight, synergistic theory-experiment loop. The research objectives of the seven proposed focus areas are summarized below:
Wireless Testbed: An existing and functioning wireless testbed will be leveraged to build an experimental system which forms the bedrock of the proposed research. This flexible design permits operation at multiple frequencies, with multiple bandwidth and array capabilities.
Multiple Access Signaling: Advanced multi-user receivers will be designed by considering novel characterizations of multiple access interference, inherent parameter mismatch, and systems that offer multiple data rates. Coupled model order selection/parameter estimation techniques will be employed to optimally characterizecand mitigate interference.
Space-Time Modems: Traditional models for space-time characteristics will be validated via field tests. Experimentally refined models will be used to optimize space-time codes. Both coupled and decoupled space-time processing algorithms will be developed to perform multi-user separation and channel equalization for multiple data rate systems.
Error Control: An interactive/iterative design process between physical layer system design and network layer protocol design will be employed to efficiently distribute system complexity. To this end, experimental error statistics will be characterized and error statistic shaping methods will be developed. For given error statistics, optimal protocols will be designed and analyzed.
Access Methods: Based on the error characteristics drawn from experimental data, we will design medium access control protocols to support timely establishment of message streams and to support different levels of temporal QoS in the presence of channel errors and fading.
Mobility: The testbed will be used to study how the channel error and fading characteristics of wireless links impact the design of a robust handoff mechanism and how error characteristics can be shaped and tuned to facilitate the design.
Flow Control: Flow control is an important resource management problem for reliable data transmission, especially in a high demand situation. A stable, robust, adaptive controller design scheme will be developed for a class of time-varying, time-delay system models appearing in basic flow control problems of communication networks.
This research project addresses several of the priorities established by the NSF for sponsored research programs. The project has been designed to be collaborative and interdisciplinary and each problem has been specifically chosen to take advantage of existing and proven expertise of the OSU team. Additionally, successful achievement of the research objectives necessitates the merging of theoretical and experimental activity. The project leverages existing facilities, but will also improve the infrastructure for future research and educational endeavors. Graduate student training will play a major role in the execution of the proposed research and the unique dual theoretical and experimental nature of the work will offer an enriched educational environment.
