Title page for ETD etd-04222003-164104

Type of Document

Master's Thesis

Author

Krishnamoorthy, Seshagiri

Author's Email Address

sesh@vt.edu

URN

etd-04222003-164104

Title

Interference Measurements and Throughput Analysis for 2.4 GHz Wireless Devices in Hospital Environments

Degree

Master of Science

Department

Electrical and Computer Engineering

Advisory Committee

Advisor Name	Title
Reed, Jeffrey Hugh	Committee Chair
Srikanteswara, Srikathyayani	Committee Member
Sweeney, Dennis G.	Committee Member

Keywords

Microwave Ovens
2.4 GHz ISM
Hospital Environments
Electromagnetic Interference (EMI)
Bluetooth throughput
WLAN

Date of Defense

2003-04-21

Availability

unrestricted

Abstract

In recent years, advancements in the field of wireless communication have led to more innovative consumer products at reduced cost. Over the next 2 to 5 years, short-range wireless devices such as Bluetooth and Wireless Local Area Networks (WLANs) are expected to become widespread throughout hospital environments for various applications. Consequently the medical community views wireless applications as ineludible and necessary. However, currently there exist regulations on the use of wireless devices in hospitals, and with the ever increasing wireless personal applications, there will be more unconscious wireless devices entering and operating in hospitals. It is feared that these wireless devices may cause electromagnetic interference that could alter the operation of medical equipment and negatively impact patient care. Additionally, unintentional electromagnetic radiation from medical equipment may have a detrimental effect on the quality of service (QoS) of these short-range wireless devices.

Unfortunately, little is known about the impact of these short-range wireless devices on medical equipment and in turn the interference caused to these wireless devices by the hospital environment. The objective of this research was to design and develop an automated software reconfigurable measurement system (PRISM) to characterize the electromagnetic environment (EME) in hospitals. The portable measurement system has the flexibility to characterize a wide range of non-contiguous frequency bands and can be monitored from a remote location via the internet. In this work electromagnetic interference (EMI) measurements in the 2.4 GHz ISM band were performed in two hospitals. These measurements are considered to be very first effort to analyze the 2.4 GHz ISM band in hospitals.

Though the recorded EMI levels were well within the immunity level recommended by the FDA, it can be expected that Bluetooth devices will undergo a throughput reduction in the presence of major interferers such as WLANs and microwave ovens. A Bluetooth throughput simulator using semi-analytic results was developed as part of this work. PRISM and the Bluetooth simulator were used to predict the throughput for six Bluetooth Asynchronous Connectionless (ACL) transmissions as a function of piconet size and interferer distance.

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