Design and implementation of a Bluetooth signal strength based location sensing system

This work proposes a location sensing system based on the widely available Bluetooth medium, and discusses problems which arise when the Bluetooth RSSI is used as a signal strength indicator, and proposes a novel access point that supports variable attenuators to overcome these problems.

Abstract

In a ubiquitous computing environment, location awareness is a basic necessity. There are various research projects, which discuss the problem of indoor location sensing. We have recognized acceptability, low power consumption, and cost as the key design factors for developing widely deployable location sensing systems. As a good candidate technology that could satisfy these needs, we proposed a location sensing system based on the widely available Bluetooth medium. Location evaluation is preformed by sensing Bluetooth signal strength with a reference model based approach. We discuss problems which arise when the Bluetooth RSSI (received signal strength indicator) is used as a signal strength indicator, and propose a novel access point that supports variable attenuators to overcome these problems. This access point allows the reading of a wider range of signal strengths using RSSI. We show that our approach to location sensing has reduced the error rate about threefold compared to systems which do not use variable attenuator supported access points.