WLPS consists of a dynamic base station (DBS) and a number of transceivers. The transceiversí location is determined by the DBS via time-of-arrival (TOA) and direction-of-arrival (DOA) estimation. DOA estimation requires an antenna array to be installed at the DBS receiver. In addition, antenna array beam-forming techniques are applied to increase the performance of the WLPS system.
Our research is focused in the following areas:
1. Development of beam-forming (BF) techniques to increase wireless positioning performance: The special signaling structure of WLPS needs well-tailored BF techniques. In addition, attention needs to be dedicated to the development of BF schemes in correlated channels to address the application of WLPS in urban and indoor areas. Capacity and performance of WLPS with various BF techniques were studied. Currently, one graduate student is involved in this area.
2. Development of direction-of-arrival (DOA) schemes: DOA needs to be accurately estimated to enhance positioning performance. Novel DOA estimation techniques for WLPS are under investigation. Currently, one graduate student is involved in this area.
3. Investigation of transceiver implementation based on ultra-wideband (UWB) signaling: To realize the full potential of UWB radios for fine-resolution wireless positioning, research is needed not only in TOA estimation, but also in resolving implementation challenges caused by over-GHz fast digital sampling. A new transceiver paradigm is under investigation to cope with the aforementioned technical and implementation challenges. Currently, one graduate student is involved in this area.
4. Investigation of the fundamental limits in localization: Analytic performances of TOA and DOA estimators would shed light on the behavior of WLPS under various operating environments. To this end, fundamental limits are investigated with regard to the Cramer-Rao lower bound (CRLB) of TOA, DOA and position estimation, as well as the geometric dilution of precision (GDOP). Such results will help to guide system tradeoffs and resource allocations. Currently, one graduate student is involved in this area.