In Partial Fulfillment of the Requirements for the Degree of
Doctor of Philosophy
Will defend his pre-defense
Guaranteeing desirable Quality of Service (QoS) levels is not only a problem for conventional real-time systems; it has also become the dominant concern in other fields, especially wired/wireless communications. For example, technologies for networked hard real-time systems, such as controlling hardware remotely for the space programs, have been applied to telemedicine systems. However, there are problems in applying current general-purpose wireless networking technology and devices for the medical domain. In this research, we focus on QoS assurance issues on wireless body monitoring systems that are battery-powered medical sensor devices. These devices are used to transmit life-critical information to the central monitoring server within the specific deadline. To support these medical wireless devices, the most widely used medium layer control (MAC) layer protocols, such as IEEE 802.11a/b/g, can be applied. However, these MAC layer protocols are incapable of providing QoS assurance for real-time/life-critical applications in general. To support real-time applications, IEEE 802.11e has been provided on MAC layer, which is initially intended to support multimedia streaming applications. However, it still has critical limitations to provide the QoS assurance to wireless medical devices. In this research, we carefully analyze the QoS requirements for medical applications, and investigate potential problems of the IEEE 802.11e standard for medical wireless devices. We then revise the current admission control mechanism in the IEEE 802.11e Enhanced Distributed Channel Access (EDCA) access scheme and provide a method to detect malicious stations to protect data traffics from wireless medical devices.