Multiple Subcarrier Indoor Geolocation System in MIMO-OFDM WLAN APs Structure

This report aims to utilize existing and future Multiple-Input Multiple-Output Orthogonal Frequency Division Multiplexing Wireless Local Area Network (MIMO-OFDM WLAN) systems characteristics–such as multiple subcarriers, multiple antennas, and channel estimation characteristics–for indoor location estimation systems based on the Direction of Arrival (DOA) and Radio Signal Strength Indication (RSSI) methods. Hybrid of DOA-RSSI methods also evaluated. In the experimental data result, we show that location estimation accuracy performances can be increased by minimizing the multipath fading effect. This is done using multiple subcarrier frequencies over wideband frequencies to estimate one location. The proposed methods are analyzed in both a wide indoor environment and a typical room-sized office. In the experiments, WLAN terminal locations are estimated by measuring multiple subcarriers from arrays of three dipole antennas of access points (AP). This research demonstrates highly accurate, robust and hardware-free add-on software for indoor location estimations based on a MIMO-OFDM WLAN system.

• Abdul Hafiizh
• Shigeki Obote
• Kenichi Kagoshima

• Direction of Arrival (DOA)
• Indoor location estimation method
• Multipath Fading
• MIMO-OFDM
• Received Signal Strength Indication (RSSI)
• WLAN
• Hybrid DOA-RSSI

[1] D.H. Shin, T.K. Sung, "Comparisons of error characteristics between
TOA and TDOA positioning", IEEE Trans. on Aero. and Elect. Sys., Volume 38, Issue 1, pp.307 - 311, Jan. 2002
[2] A. Ogino, K. Tsunehara, K. Watanabe, K. Fujishima, R. Yamasaki, H. Suzuki, T. Kato, "Integrated Wireless LAN Acees System-Study on
Location Method," Multimedia, Distributed, Cooperative, and Mobile Symposium (DICOMO 2003), June 2003.
[3] http://www.ekahau.com/
[4] P. Bahl, V. N. Padmanabhan, "RADAR: An In-Building RF based user
location and tracking system," Proceed. of IEEE INFOCOM 2000,
Tel-Aviv, Israel, March 2000.
[5] Li Cong; W. Zhuang, "Hybrid TDOA/AOA mobile user location for
wideband CDMA cellular systems ", IEEE Trans. on Wireless Comm.,
Vol. 1, Issue 3, pp. 439 - 447, July 2002.
[6] J. Terada, H. Takahashi, Y. Sato, S. Mutoh, "A novel location-estimation
method using direction-of-arrival estimation," 62nd IEEE Veh. Technol.
Conf., vol. 1, pp. 424- 428, Sept. 2005.
[7] H. Tsuji " Indoor localization using signal subspaces obtained from array antenna-an experimental evaluation", IEICE Technical Report (In
Japanese), AP2006-80, October 2006.
[8] K. Kaemarungsi and P. Krishnamurthy, "Modeling of indoor positioning
systems based on location fingerprinting," in Proc. 23rd. Annual Joint
Conference of the IEEE Computer and Communications Societies, vol. 2, pp. 1012-1022, Mar. 2004.
[9] Y. Karasawa, "MIMO Propagation Channel Modeling (Japanese
Edition)", IEICE Trans. on Comm., Vol.E88-B, No.5, pp.1829-1842,
May 2005.
[10] K. Sakaguchi, H.Y.E. Chua, K. Araki, "MIMO Channel Capacity in an
Indoor Line-Of-Sight (LOS) Environment", IEICE Trans. on Comm., Vol.E88-B, No.7, pp.3010-3019, July 2005.
[11] A. Hafiizh, F. Imai, M. Minami, K. Ikeda, S. Obote, K. Kagoshima, "Performance Study of DOA-based Indoor Location Positioning Utilizing
MIMO Wireless LAN System", ISAP 2006, 1-4 October 2006, Singapore.
[12] A. Hafiizh, F. Imai, M. Minami, K. Ikeda, S. Obote, K. Kagoshima, "Study of DOA-based indoor location positioning utilizing MIMO
WLAN system in typical room environment", ISAP 2008, 20-24 August 2007, Niigata Japan.
[13] B.D.V. Veen and K. M. Buckley "Beamforming:A versatile approach to
spatial filtering", IEEE ASSP Mag., pp 4-24, April 1988.
[14] N. Kikuma, "Adaptive Signal Processing with Array. Antenna (Japanese
edition)", Tokyo, Japan: Science and. Technology Publishing Company,
Nov. 1998.