802.11 WLAN OWPT measurement algorithms and simulations for indoor localization

Abstract

This paper discussed novel algorithms for synchronizations and time resolution improvements of One Way Propagation Time (OWPT) measurements in the 802.11 Wireless Local Area Network (WLAN). In OWPT measurements, the Mobile Station (MS) records each 802.11 Beacon frame’s arrival time. The Beacon frame’s arrival time minus its Timestamp, which is recorded when the Beacon frame is transmitted from an Access Point (AP), is the Beacon frame’s Propagation Time. The Propagation Time represents the distance between the MS and the AP. Rather than microseconds (μs) time resolution Timestamp, the MS could use its high precision clock to record the Beacon frame’s arrival time in nanoseconds (ns). The first part of this paper proposes algorithms which can utilize the ns resolution arrival Time to improve the OWPT measurements time resolution from μs to ns and to highly synchronize the MS with all APs. These algorithms provide an opportunity to apply OWPT in 802.11 WLAN for highly accurate indoor localization. The second part discusses the possibility to utilize existing software and hardware platform to realize the proposed algorithms. At the end of this paper, the shortages of existing MS timing ability were raised and several options are provided for future researches to improve MS timing ability for OWPT application.