WLAN and RFID Propagation channels for hybrid indoor positioning

Abstract

Indoor localization based on Received Signal Strengths (RSS) or on some form of power measurements is a low-cost and low-complexity solution gaining more and more interest in the research and commercial worlds. Typically, Wireless Local Area Network (WLAN) signals are employed for such purpose, due to the fact that they are widely spread in indoor environments. Nevertheless, any wireless signal available in indoor scenarios can be used for positioning based on similar power measurement approaches. One example is the radio frequency identification (RFID), which enable portable localization systems in the form of wearable RFID tags. Such RFID-enabled systems are highly demanded for health-state monitoring, object tracking, and security. These applications are mostly indoor applications, and thus, we can envision a near future where multiple RFID and WLAN signals will co-exist on multiple frequency bands. The existing signal diversity can offer a benefit in indoor positioning, providing that the signal propagation effects for both WLAN and RFID are well understood and taken into account. However, measurement-based studies on indoor channel modeling, including path loss and shadowing effects of RFID signals are still missing. A comparison between RFID and WLAN channel models for positioning purpose has yet to be made. It is the purpose of our paper to address the path-loss channel models and shadowing effects for WLAN and RFID signals based on extensive measurement campaigns in an office environment.

Indoor location identification technologies for real-time IoT-based applications: An inclusive survey

“…Hence, we advocate increased hybridization of technologies as an effective approach to achieving reliable IoT-based indoor systems. Although the advantages of hybridization are being exploited by different authors, who have ''navigated'' their research interest towards this direction [302][303][304][305][306][307][308][309][310][311][312][313][314][315], however, an increased exploitation of hybridization would raise the bar towards attaining a more robust, reliable IoT-based indoor applications and systems.…”

Hybrid WLAN-RFID Indoor Localization Solution Utilizing Textile Tag

“…In Fig.5 we show what happens when only N out of the four RFID readers are used, N=1,…4. Clearly, more RFID readers are (1) The RFID statistics are room-based and using the true Reader possitions (known) (2) The WLAN statistics are building-based and using the estimated AP positions via the weighted centroid approach [3]. Fig.…”

“…The data collection for the WLAN was done similarly with [2] [3]. In the same measurement room as above, the WLAN data have been collected utilizing a Nexus tablet with HERE maps.…”

Indoor Positioning and Fingerprinting: The R Package ipft

“…The σ 2 parameter represents the shadowing variance (Shrestha et al, 2013). Values for σ in the range between 4 and 10 dBm are usually good for indoor scenarios (Lohan et al, 2014).…”