Research Contributions:

In a BAA 04-031 project between CWINS/WPI and Draper Laboratory, the primary objective is to enable accurate, robust localization and tracking of people/assets/objects in indoor environments.

This will be accomplished by developing a signal processing methodology and algorithms which address several fundamental limitations of existing active, passive, or aided concepts. This development will be based on localization and tracking of electronic tags capable of receiving and retransmitting (with or without alteration) signals received from known signal sources located within a local network. The key innovation is to more fully exploit the diversity of measurement phenomena and unique waveform characteristics of indoor RF multipath signals. Measurements of received signal strength, angle of arrival, time of arrival, time difference of arrival and Doppler will be exploited, as appropriate, for each individual multipath signal element.

CWINS works on the analysis and modeling of the multipath and performance of traditional algorithms and Draper Laboratory works on algorithms exploiting multipath diversity.

In this project CWINS and IWT, a small wireless radio development firm, join forces to design an MB-OFDM UWB system with indoor positioning capabilities.

The main contribution of CWINS is to characterize UWB RF propagation in various environments and develop indoor positioning algorithms that support accurate indoor positioning in an adhoc networking environment. IWT will design the hardware for implementation of the actual communication network. Phase I of this project was completed successfully and we are awaiting the start of Phase II.

In this project Prof. Pahlavan’s group used the UWB measurements in 3-6GHz bands to develop a novel model for indoor geolocation. The model was then used for evaluation of indoor geolocation algorithms.

The principal research goal of this project was to provide a foundation for the indoor geolocation science needed in the design and performance evaluation of indoor geolocation systems.

Two specific research objectives in this project were:

• • • To analyze the multipath characteristics of the indoor radio propagation that affect the performance of indoor geolocation systems through empirical broadband measurements in typical sites, and design of statistical measurement-based and geometrical models for the behavior of the channel.
    • To use the results of objective 1 to lay a foundation for the design and performance evaluation of distributed indoor geolocation systems capable of locating objects in smart indoor spaces where numerous unreliable sources interact to provide an accurate location of each element.

For the first objective indoor channel measurements of the TOA of the first path at GHz frequencies were performed to prepare a database for future research in this field. The measurement data base includes LOS and NLOS measurements. Results of these measurements were used to analyze the effectiveness of the super-resolution algorithms. Also, a novel model for the distance measurement error for indoor geolocation was developed under this project.

Using the funding in this project CWINS purchased a PROPSim C8 hardware platform for development of a real time RF channel simulation environment. PROPSim is currently the world’s leading hardware platform used for real time simulation of wireless channel behavior for cellular networks and WLANs. In addition to simulation for traditional communication systems, the platform can simulate geolocation and smart antenna environments vital to modern military and commercial communication projects. The simulator allows us to test modern telecommunication and geolocation systems quickly and thoroughly under controlled, realistic, and repeatable channel conditions in the laboratory, thereby reducing the time and cost of field tests through improved and better focused test planning.

The objective of this project was to implement an urban geolocation demonstrator. In the course of the project, it was discovered that due to severe multipath conditions in urban and indoor areas traditional GPS receivers are unable to provide an accurate measurement of the location of objects within the buildings.

Preliminary results of ray tracing simulation and initial measurements showed that in many situations the signal arriving from the direct path (DP) is not the strongest signal arriving at the receiver. Traditional receivers, however, lock to the path associated with the strongest received signal. Therefore, the estimated distance found with traditional receivers may correspond to an arbitrary distance that includes a number of reflections of the signal before it arrives at the receiver. This observation revealed a need for research in modeling of the indoor radio channel and design of new signal structures and algorithms for indoor geolocation that led to other indoor geolocation projects pursued at WPI.

The preliminary results of this project were presented in several DARPA open review workshops, two DARPA reports, and several pioneering papers and presentations

In this project CWINS, WPI and CWC, University of Oulu Finland received funding from TEKES, Nokia, and Finnish Air force to work on traffic engineering and architecture of IGT-WIN systems.

This project was focused on practical telecommunication aspects in the design of PHY and MAC layers and in the general architecture of the network. Design of system architecture and traffic engineering for IGT-WIN networks were in its infancy. A good solution for this problem involves understanding the worldwide evolution of products and standards. For this reason CWINS-CWC team that has interaction with Nokia and other leading commercial wireless companies is an ideal team to pursue this design.

The specific goals of this project were to study the architecture of the existing geolocation products, study the progress in PHY and MAC layer design for Bluetooth and Home RF projects, design PHY and MAC layers to support both geolocation and telecommunication applications, and design an architecture for the Vo-IP network. The project resulted in several graduate theses in the US and Finland.