Seminar Series
Maryland Information and Network Dynamics Laboratory
Maryland Information and Network Dynamics Laboratory
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›› MIND Lab Seminar Series: 5 November 2008
Characterization of IEEE 802.11 Wireless Chipsets
Matt Fichman
Undergraduate Student in Computer Engineering
›› Logistics
Please note location, date, and time change.
Date: Wednesday, November 5, 2008
Time: 12:30p to 1:30p
Location: AVW 4424
›› Abstract
The IEEE 802.11 (WiFi) standard is perhaps the most popular short-range wireless network standard; a nearly endless variety of chipsets implementing IEEE 802.11 have been developed, each with its own unique properties. A comprehensive understanding of these properties has become necessary in recent experiments using the Horus and PinPoint WiFi-based location determination systems. The goal of this study is to identify important properties (including RSSI scaling and clock drift) and characterize them for a wide range of chipsets. A characterization of WiFi chipsets has immediate applications in the Horus radio map construction stage and in the PinPoint time-difference calculations.
Horus and PinPoint Background
Horus is a system that builds a radio map of an area with high Wi-Fi network density by observing the received signal strength indication (RSSI) of nearby wireless access points. The system is effective, but works only with a select wireless chipsets because each chipset has a different RSSI scaling. Horus could be improved by finding the correlation between the RSSIs of different wireless chipsets.
PinPoint is described as an "asynchronous time-based location determination system." Using the PinPoint time-difference algorithms, the distance between two nodes in a wireless network can be determined. The algorithms do not require synchronized clocks to determine the time-distance between two nodes. In practice, however, a characterization is needed for change in the rate of clock drift between nodes.
Therefore characterizations of the RSSI scaling and onboard clock frequency of several wireless network chipsets are required. The goal of this project is to provide the needed characterizations in support of the Horus and PinPoint projects.