Composcan: adaptive scanning for efficient concurrent communications and positioning with 802.11

Using 802.11 concurrently for communications and positioning is problematic, especially if location-based services (e.g., indoor navigation) are concurrently executed with real-time applications (e.g., VoIP, video conferencing). Periodical scanning for measuring the signal strength interrupts the data flow. Reducing the scan frequency is no option because it hurts the position accuracy. For this reason, we need an adaptive technique to mitigate this problem. This work proposes ComPoScan which, based on movement detection, adaptively switches between light-weight monitor sniffing and invasive active scanning to allow positioning and to minimize the impact on the data flow. The system is configurable to realize different trade-offs between position accuracy and the level of communication interruption. We provide extensive experimental results by emulation on data collected at several sites and by validation in several realworld deployments. Results from the emulation show that the syste...

• Type: Conference
• Year: 2008
• Where: MOBISYS
• Authors: Mikkel Baun Kjærgaard, Thomas King
• Keywords: MOBISYS 2008, Position Accuracy, Positioning Accuracy, Signal Strength Measurement, Wireless Networks