Research Challenges in Wireless Networks of Biomedical Sensors1

Loren Schwiebert

Wayne State University

Department of Computer Science

1This material is based upon work supported by the National Science Foundation under Grants ANI-0086020 and DGE-9870720 and the Kresge Eye Institute.

Sandeep K. S. Gupta

Arizona State University

Department of Computer Science and Engineering

Jennifer Weinmann

Wayne State University

Department of Electrical and Computer Engineering

Additional Authors: Ayad Salhieh, Vikram Shankar, Valliappan Annamalai, Manish Kochhal, and Greg Auner.

“Typical” Future Sensor Node

• Matchbox Size• Battery Powered• Power-conserving processor – 100’s of

MHz• 10’s of MB of program and data memory• Radio modem using TDMA• Capable of running a scaled down version

of Palm OS or Windows CE

Biomedical Smart Sensors??

• Smart Sensor – Biomedical sensor/actuator with integrated circuitry

• Biomedical – Implanted in the human body

• Form – Small with limited power, encased in inert material

• Function – Alleviate chronic diseases and disabilities, monitor health

Biomedical Sensors are Unique!

• Limited Computation and Data Storage• Ultra Low Power Consumption• Wireless Communication• Continuous Operation• Inaccessibility• Bio-Compatibility – Material Constraints• Robustness and Fault Tolerance• Secure Data Communications• Regulatory Requirements

Example Applications

• Glucose Level Monitor

• Transplant Organ Viability Monitor

• Blood Monitor

• Retinal and Cortical Prosthesis

• Cancer Detection/Monitor

• Health Monitor

Retinal and Cortical Implant

Data Processing and Communication

Smart Sensor Retinal Interface

Functional Block Diagramof the Retinal Neuron Scanner

Research Approach

• Optimize across protocol layers• Organize communication among sensor

nodes• Develop application-specific solutions• Take advantage of biomedical sensor

features – fixed topology, pre-defined communication and known membership

• Generalize these solutions

Research on Fixed Topologies

• Vary # of Neighbors• Trade-offs Exist

– Number of Hops

– Number of Receivers

– Amount of Contention

• Evaluate Power Usage• Test Power-Aware

Routing

Research on Fixed Topologies

• Power-Aware Routing reduces Power Usage

• 3D is better than 2D• 4 Neighbor Topology

has lower Power Use• Reason is always

fewer Receptions• Current work includes

improving protocols

Research Objectives

• Strict Power Management

• Efficient Wireless Spectrum Use

• Scalability – Support as Many Sensing Elements as Possible

• Support Diagnostic Functionality

• Standardize Design with Other Research Groups

Smart Sensors and Integrated Devices

Materials Development

Device Development and Prototyping

Electronic Integration Design

Hybrid Technology and Packaging

Device Characterization, Testing, and Evaluation

Materials Characterization (Microstructure, optical, electrical)

Materials Simulation, Device Simulation, Design, and Testing

Materials Processing (Special lithography and

device fabrication development)

Device Simulation Design and Testing

Data Communications and Interface Design

VLSI Circuit Development Intelligent system Design and Development (Neuronet, logic)

Multidisciplinary Research

Smart Sensors and Integrated MicrosystemsGregory W. Auner, PhDPepe Siy, PhDLoren Schwiebert, PhDVaman Naik, PhDRatna Naik, PhDLowell Wenger, PhDXiaoyan Han, PhDYuriy Danylyuk, grad studentDan Durisin, engineerFrancette Fey, grad student (NSF IGERT)Sam George, research assistantChanghe Huang, PhDChantelle Hughes, grad student (NSF IGERT)Michael Lukitsch, grad student (NSF IGERT)Marvie Nickola, grad student (NSF IGERT)Mona Safadi, grad student (NSF IGERT)David Sant, grad studentFlaminia Serina, M.S. (NSF IGERT)Margarita Thompson, PhDJennifer Weinmann, grad student (NSF IGERT)Jie Xu, professorSong Xu, PhDFeng Zhong, grad studentAyad Salhieh, grad student (NSF ITR)Manish Kochhal, grad student (NSF ITR)Changli Jiao, grad student

Retina and Cortical Implant Project

OphthalmologyGary Abrams, MDRaymond Iezzi, MDAlexander Dizoor, PhD

NeurosurgeryPat McAllister, PhDRobert Johnson, MDJanet Miller, B.S.Hun Park, MD, PhDTodd Frances, M.S.

VeterinarianLiz Dawe, D.V.M.