Cooperative and heterogeneous indoor localization experiments

Abstract

International audienceIn this paper we present the results of real-life localization experiments performed in an unprecedented cooperative and heterogeneous wireless context. These measurements are based on ZigBee and orthogonal frequency division multiplexing (OFDM) devices, respectively endowed with received signal strength indicator (RSSI) and round trip delay (RTD) estimation capabilities. More particularly we emulate a multi-standard terminal, moving in a typical indoor environment, while communicating with fixed OFDM-based femto-base stations (Femto-BSs) and with other mobiles or fixed anchor nodes (through peer-to-peer links) forming a wireless sensor network (WSN). We introduce the measurement functionalities and metrics, the scenario and set-up, providing realistic connectivity and obstruction conditions. Out of the experimental data, preliminary positioning results based on cooperative and geometric algorithms are finally discussed, showing benefits through mobile-to-mobile cooperation, selective hybrid data fusion and detection of unreliable nodes

Enhancing RFID indoor localization with cellular technologies

“…Compared with the state of the art, 1.5-m mean absolute error is obtained in [1], and 1 m at 80th percentile, but 4 m at 90th percentile, are obtained in [16]. Furthermore, in reference [6], the RFID system is quite similar in terms of hardware (a mesh of 19 RFID sensors and 19 active RFID reference tags) while this work uses 30 active tags for similar performances.…”

“…The main purpose of combining different technologies is to increase the accuracy [12], or the density of the devices to be localized [13], or to overcome the continuity indoor/outdoor challenge [14], where these systems need to handle heterogeneous devices [15] and vertical handovers [1]. European Project WHERE2 [16] presented results of real-life experiments based on ZigBee and orthogonal frequency division multiplexing (OFDM) devices (emulating a multistandard terminal moving in typical indoor environments), with measurements using Received Signal Strength Indicator (RSSI) and round-trip delay (RTD). A comparison between non-cooperative and cooperative positioning was done, and several positioning algorithms were tested in both cases.…”

Recent Advances in Indoor Localization: A Survey on Theoretical Approaches and Applications

“…The authors of [63], however, carried out extensive research that dealt uniquely with cooperation in homogeneous scenarios. As well, a measurement campaign in jointly heterogeneous and cooperative wireless indoor scenarios uses ZigBee devices with RSS measurement abilities [64]. HDF methods estimate reliable position information to the benefit of communications.…”

Round-trip delay indoor ranging experiments with OFDM signals

“…During preliminary experiments we identified the metalized window behind the RTD mirror as one of several major sources of multipath, [3], [15]. We were interested how RTD ranging performance is influenced if we change the environment in a controlled way.…”

“…Ranging performance of these systems is heavily degraded indoors due to multipath and signal blockage. One way to achieve improved indoor localization is by means of cooperation, and by means of fusing different radio access technologies [2], [3]. RSS from WiFi or ZigBee proved to be too inaccurate for precise indoor localization for most applications, even if cooperation is taken into account [4].…”