A Wireless Sensor Network Based Health Monitoring Infrastructure and Testbed

Department of Computer Science and Engineering, Arizona State University

Faculty Advisor

Sandeep K.S. Gupta
Department of Computer Science and Engineering
Arizona State University

Present Students

Past Students

  • Valliappan Annamalai
  • John Quintero
  • Vikram Shankar
  • Tridib Mukherjee
  • Guofeng Deng
  • Gianni Giorgetti


Past Collaborators



The health-care system in developed countries will increasingly come under pressure as the average age of their
populations increases and the number of elderly people swells. This will most likely lead to dire shortages of health-care personnel, and, if left unattended, could result in a drop in the quality of medical care and a substantial increase in health-care costs. To address this problem we are developing a sensor network based medical monitoring infrastructure called Ayushman.

We envision Ayushman to meet the following set of goals:

  • To provide a dependable, secure, real-time automated health monitoring.
  • Is scalable and flexible enough to be used in diverse scenarios from home based monitoring to disaster relief, with minimal customization.
  • To provide a realistic environment (test-bed) for testing communication protocols and systems for medical applications

Ayushman: Vision

Architectural Design

With Ayushman we are developing a dependable and secure health monitoring infrastructure that can collect, query and analyze patient health information in real-time. Ayushman's conceptual architecture organizes its essential features as a set of interacting services. There are essential 5 components to this organizations:

  • Hardware Medical Sensors: Collect the actual medical data.
  • Sensor Management Service: Provides an abstraction of the medical sensor hardware to the higher level services.
  • System Management Subsystem: Provides a set of services which provide dependable, real-time medical monitoring related functions.
  • Performance Management Subsystem: As Ayushman is a testbed for testing communicaiton components for medical applications, this subsystem in conjunction with the Performance Analyzer application can be used to monitor and control various aspects of medical monitoring component in Ayushman.
  • Security Management Subsystem: Due to the critical nature of health information, maintaining patient's privacy is important. Ayushman provides a security management subsystem which provides application controlled security and authentication services to all the components.
  • Application Layer: At the top is the application layer which provides application to control various aspects of the system including. Some of the applications include the performance analyzer, which controls the performance management subsystem, the data display manager which provides meaningful way to disaply patient data, query generator can be used to query various aspects of the medical monitoring part of the infrasturcutre, data manager is used to interpret medical data and finally the security manager is used to control the security subsystem.

Ayushman's Conceptual Architecture


Physical Organization

In the previous section we presented the conceptual architecture of Ayushman. In our current implementation however, Ayushman is organized as a three-tiered hierarchical cluster. At the lowest tier are the medical devices and sensors which collect data from the patients. The data collected by them is sent to their cluster head node called the local gateway implemented on a PDA. The PDAs form the second-tier cluster and are lead by an external gateway node implemented on a laptop and these laptops form the third-tier headed by a workstation designated the central server which manages the entire system . Each of the tier has been designed to be self contained and can survive on its own even in the event of disconnection and network partition.

Localization Capabilities Integrated into Ayushman

As a part of the Ayushman project implementation we also integrated a localization system, to provide location based medical services and access control on the systems information. The localization system was initially built to provide location based access control to computing resources in our lab. It basically uses a scene analysis based approach to localize an entity. We implemented and tested this system within our lab, as a first step we trained system by creating a signal strength based map of our lab and then used scene analysis to calculate various locations within our lab. Then when an actual entity is detected, based on the scene analysis results and signal strength of its id, it can be localized.

Localization Architecture

Implementation of the Initial Prototype

EKG and Blod Pressure Monitoring: We implemented Ayushman, using off-the-shelf components and integrated them together. Firstly we integrated an EKG monitor (Vernier EKG) and Blood-Pressure Monitor (Suntech Advantage BP monitor). These two devices do not provide any wireless communication capability, therefore they were connected to a Mica2/MicaZ mote using a serial port. The motes controlled them and provided a wireless interface to transmit their data which is eventually stored in a central server.

Oximeter: The Oximeter Sensor and board (Smith Medical) provides us with the ability to monitor in real-time a person blood oxygen level, photoplethysmogram and heart rate. The device does not provide any wireless communication capability, therefore was interfaced with a MicaZ mote using a serial port. We implemented a simple PCB board allowed us to connect the device directly to the mote through the 51pin header. The PCB performed the necessary switching between the logic levels of RS232 and MicaZ mote.The design was obtained from the CodeBlue projects. The motes controlled them and provided a wireless interface to transmit their data which is eventually stored in a central server.

Gait Monitoring: We have implemented a gait monitoring system as a part of the Ayushman system. Gait monitoring is done using accelrometer, gyroscopic sensors attached to MicaZ motes. Further we also use piezoelectric heal and toe strike sensors to detect each step. The gait analysis is done at the PC based on the data sent by these sensors.

Environment Monitoring: Further we also collect ambient information from around the patient, including temperature, humidity, along with light information. This information is corellated with the EKG, BP and Gait Monitoring sensors to obtain an accurate state of the patient's health. Environmental monitoring is done using TelosB sensors which also provided a wireless interface to transmit their data to a central server.

Software Components: Most of the backend software for Ayushman has been written in C#. The local gateway is implemented on three platforms - Dell Axim PDA and Motorola Cellphone which collects physiological data from the sensors, stores it and forwards to the central server. We have also experimented with a Crossbow Stargate platform as the local gateway with equally good results. The central sever stores all the data it receives on a MS Access database and allows remote clients to connect, view and query patient data. Priliminary experiments on the lifetime of the motes and and the PDA show that they can last for upto a month and 14 hours respectively before batteries have to be recharged.

Vernier EKG Monitor & Mica2 Motes

Gait Monitoring

Pulse Oximeter interfaced through MicaZ Mote

Oximeter-Mote Interface Board

Blood Pressure Monitor interfaced through MicaZ Mote

Blood Pressure Internals

Base Station (PDA-based)

Base Station (Cellphone-based)

Real-time Patient data at Remote Client


  • K. Venkatasubramanian, A. Banerjee, S. K. S. Gupta, Green and Sustainable Cyber Physical Security Solutions for Body Area Networks In Proc. of 6th Workshop on Body Sensor Networks (BSN'09), Berkeley, CA, June 2009. (Accepted for Publication) [PDF|PPT]

  • A. Banerjee, K. Venkatasubramanian, S. K. S. Gupta, Challenges of Implementing Cyber-Physical Security Solutions in Body Area Networks In Proc of International Conference on Body Area Networks (BodyNets'09), Los Angeles, CA, April 2009.[PDF|PPT]

  • Krishna K. Venkatasubramanian, Ayan Banerjee, Sandeep K. S. Gupta, Plethysmogram-based Secure Inter-Sensor Communication in Body Area Networks In Proc of IEEE Military Communications Conference (MILCOM'08), San Diego, CA, November 2008.[PDF|PPT]

  • K. Venkatasubramanian, S. K. S. Gupta, Demo - AYUSHMAN: A Secure, Usable Pervasive Health Monitoring System, Proceedings of the 1st ACM SIGMOBILE International Workshop on Systems and Networking Support for Healthcare and Assisted Living Environments, HealthNet 2008, ACM Mobisys Workshops, Breckenridge, CO, June, 2008. [PDF]
  • Krishna Kumar Venkatasubramanian, Ayan Banerjee, Sandeep Gupta, EKG-based Key Agreement in Body Sensor Networks, In Proc. of 2nd Mission Critical Networks Workshop, IEEE Infocom Workshops, Phoenix, AZ, April 2008. [PDF| PPT]
  • K. Venkatasubramanian, S. K. S. Gupta, Chapter 15: Security for Pervasive Healthcare, pp 443-464, In Security in Distributed, Grid, Mobile, and Pervasive Computing, eds. Yang Xiao, Auerbach Publications, CRC Press, 2007. [PDF]
  • G. Giorgetti, G. Manes, J.H. Lewis, Sal T. Mastroianni, S.K.S. Gupta, The Personal Sensor Network: A User-Centric Monitoring Solution In Proc. of 2nd International Conference on Body Area Networks, June 2007, Florence, Italy [PDF| PPT]
  • K. Venkatasubramanian, S. K. S. Gupta, Security For Pervasive Health Monitoring Sensor Applications In Proc. of 4th International Conference on Intelligent Sensing and Information Processing (ICISIP'06), Bangalore, India, December 2006, pp 197-202 [PDF| PPT] (Received Best Paper Award)
  • Sandeep K.S. Gupta, G. Giorgetti, K. Venkatasubramanian Abstract- Pervasive Point-of-Care Treatment Using AYUSHMAN – An Infrastructure for Wireless Biosensors-Based Health Monitoring, In Proc. of Moving Biosensors to Point-of-Care Cancer Diagnostic Conference, Rockville, MA, June, 2005. [PDF]
  • K. Venkatasubramanian, G. Deng, T. Mukherjee, J. Quintero, V. Annamalai and S. K. S. Gupta, Poster - Ayushman: A Wireless Sensor Network Based Health Monitoring Infrastructure and Testbed, In Proc. of IEEE International Conference on Distributed Computing in Sensor Systems (DCOSS), June 2005 [PDF]
  • Krishna Venkatasubramanian, Guofeng Deng, Tridib Mukherjee, John Quintero, Valliappan Annamalai and S. K. S. Gupta, Poster - Ayushman: A Wireless Sensor Network Based Health Monitoring Infrastructure and Testbed (Shorter Version), Lecture Notes in Computer Science, Springer Verlag, Vol. 3560, 2005 [PDF]
  • Ayushman - Student Poster , Presented at SenSip April, 2005 [Image]


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Last Updated: 11th May 2008

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