Center for Telecommunication Circuits and Systems (C1) Proposal #1127956 Proposal #1127926
This proposal seeks funding for the Center for Telecommunication Circuits and Systems (C1) located at the University of Hawaii site and the Arizona State University site, respectively. Requests for Fundamental Research are authorized by an NSF approved solicitation, NSF 10-601. The solicitation invites I/UCRCs to submit proposals for support of industry-defined fundamental research.
This proposal requests NSF funding to develop a novel low-cost and highly integrated microwave based vital signs monitoring device, namely a "microwave stethoscope," that can continuously collect human vital sign data with minimal discomfort to the patient. The vital signs to be measured include the heart rate, breathing rate, stroke volume, and lung water content. The estimation of water distribution in the lungs is also proposed through the use of an array of such applicators with the proper development of array digital signal processing (DSP) algorithms. The development of such a microwave sensor together with the compact, low-cost, low power receiver circuitry and the associated DSP algorithms will allow the mobile use of the device and open broad areas of applications in healthcare patient monitoring, screening of school students, as well as variety of military applications.
Successful completion of this project will enable improving healthcare in remote and under privileged communities, and in supporting a variety of in-field and emergency military applications. The developed hardware platform can be an investigative tool for further illness diagnosis. This project will enable use of millimeter wave integrated circuits for high accuracy monitoring of human health, and provides a new diagnosis tool to a wide array of medical doctors including epidemiologists, pediatricians, and family physicians.
What are the major goals of the project? Doppler radar can be used to measure respiration and heart rate without contact and through obstacles. In this work, Doppler radar architecture at 2.4 GHz and a new signal processing algorithm to estimate the respiration and heart rate are presented. The received signal is dominated by the transceiver noise, LO phase noise and clutter which reduces the signal-to-noise ratio of the desired signal. The proposed architecture and algorithm are used to mitigate these issues and obtain an accurate estimate of the heart and respiration rate. Quadrature low-IF transceiver architecture is adopted to resolve null points in the received signal as well as avoid noise and DC offset due to mixer-LO coupling. Adaptive clutter cancellation algorithm is used to enhance receiver sensitivity coupled with a novel Pattern Search in Noise Subspace (PSNS) algorithm to estimate respiration and heart rate. PSNS is a modified MUSIC algorithm which uses the phase noise to enhance Doppler shift detection. A prototype system was implemented using TI and RFMD transceiver parts and tests were conducted with eight individuals. The measured results shows accurate estimate of the cardio pulmonary signals in low SNR conditions and have been tested up to a distance of 6 meters. What was accomplished under these goals (you must provide information for at least one of the 4 categories below)? Major Activities: Design of a Doppler radar transceiver operating at 2.4GHz band. Quadrature low-IF transceiver architecture is adopted to resolve null points in the received signal as well as avoid 1/f noise and DC offset due to mixer-LO coupling. Adaptive clutter cancellation algorithm is used to enhance receiver sensitivity coupled with a novel Pattern Search in Noise Subspace (PSNS) algorithm to estimate respiration and heart rate. Specific Objectives: Vital sign monitoring through Doppler radar provides a method to accurately estimate respiration and heart rate of a relatively still subject without contact and through their clothing. In this project, the objective is to develop a transceiver by using readily and cheaply available RFICs and demonstrate the ability to measure heart and respiration rate up to 6m in the presence of strong clutter. Significant Results: In this project we address fundamental issues associated with remote vital sign monitoring and propose novel system architecture and signal processing algorithms to mitigate them. We propose adaptive clutter cancellation for a low-IF architecture and Pattern Search in Noise Subspace (PSNS) algorithm to estimate respiration and heart rate. PSNS is an enhancement to MUSIC algorithm which using the knowledge of transmitted phase noise to enhance Doppler shift detection making it immune to spurious peaks due to phase noise. Using these techniques, estimation of heart and respiration rate up to 6m has been achieved. Key outcomes or other achievements: An autonomous system that can be used for remote sensing of vital signal is proposed. Fig. 1 shows of the developed system and hardware implementation of this system. What opportunities for training and professional development has the project provided? Two graduate students worked on this project. One of the students were responsible for the hardware platform shown in Fig. 1 and another student worked on the signal processing algorithms. This project gave them an opportunity to have a hands-on system level engineering design experience. How have the results been disseminated to communities of interest? Currently, a journal article is written on the project targeted for IEEE Transactions on Biomedical Circuits and Systems. What do you plan to do during the next reporting period to accomplish the goals? Our plan for the next phase of this project, we would like to integrate the transceiver on a single piece of silicon, minimizing power, weight and size of the transceiver.