This paper proposes a technique of the source location estimation with the modulated scattering technique (MST) for indoor wireless environments. The uniform circular scatterer array (UCSA) that consist of five optically modulated scatterers as array elements and a dipole antenna at the center of the UCSA is employed for estimating a source location from the impinging signal. In contrast with a conventional uniform circular array (UCA), the proposed method using the MST needs only one RF path. Also, the plane-wave assumption of the impinging signal is not necessary for an array signal processing because the proposed method is based on a phaseless measurement. Therefore, the proposed method can be applied in short-range LOS and NLOS environments that the plane-wave signal cannot be formed. A source location is estimated by using a simple estimation algorithm based on the power difference of the scattering signals modulated by two scatterers on the UCSA. The power difference is caused by different propagation losses between a source and each scatterer. The performance of the proposed method is demonstrated by measuring the angles of the incoming signals in the anechoic chamber and by comparing the estimated angles with the simulated results.
2. Kim, R. Y., J. S. Kwak, and K. Etemad, "WiMAX femtocell: requirements, challenges, and solutions," IEEE Communications Magazine, Vol. 47, No. 9, 84-91, Sep., 2009.
3. Chandrasekhar, V., J. Andrews, and A. Gatherer, "Femtocell networks: A survey," IEEE Communications Magazine, Vol. 46, No. 9, 59-67, Sep., 2008.
4. Godara, L., "Apprication of antenna arras to mobile communications, part II: Beam-forming and direction-of-arrival considerations," Proceedings of the IEEE, Vol. 85, No. 8, 1195-1245, 1997.
5. Krim, H. and M. Viberg, "Two decades of array signal processing research," IEEE Signal Processing Magazine, Vol. 13, No. 4, 67-94, Jul., 1996.
6. Chen, J. C., Y. Kung, and R. E. Hudson, "Source localization and beamforming," IEEE Signal Processing Magazine, Vol. 19, No. 2, 30-39, Mar., 2002.
7. Taillefer, E., A. Hirata, and T. Ohira, "Direction-of-arrival estimation using radiation power pattern with an ESPAR antenna," IEEE Trans. Antennas and Propagation, Vol. 53, No. 2, 678-684, 2005.
8. Plapous, C., J. Cheng, E. Taillefer, A. Hirata, and T. Ohira, "Reactance domain MUSIC algorithm for electronically steerable parasitic array radiator," IEEE Trans. Antennas and Propagation, Vol. 52, No. 12, 3257-3264, 2004.
9. Hwang, S., S. Burintramart, T. K. Sarkar, and S. R. Best, "Direction of arrival (DOA) estimation using electrically small tuned dipole antennas," IEEE Trans. Antennas and Propagation, Vol. 54, No. 11, 3292-3301, 2006.
10. Sun, C. and N. C. Karmakar, "Direction of arrival estimation with a novel single-port smart antenna," EURASIP Journal on Applied Signal Processing, Vol. 2004, No. 9, 1364-1375, 2004.
11. Taillefer, E., W. Nomura, and M. Taromaru, "New direction-of-arrival estimation method based on the reactance-domain ESPRIT algorithm with improved subarray-configuration selection," The 9th European Conference of Wireless Technology, 55-58, 2006.
12. Wu, Y. and H. C. So, "Simple and accurate two-dimensional angle estimation for a single source with uniform circular array," IEEE Antenna Wireless Propagat. Lett., Vol. 7, 78-80, 2008.
13. Hygate, G. and J. F. Nye, "Measuring fields directly with an optically modulated scatterer," Measure. Sci. Technol., Vol. 1, 703-709, 1990.
14. Choi, J. H., J. I. Moon, and S. O. Park, "Measurement of the modulated scattering microwave fields using dual-phase lock-in amplifier," IEEE Antenna Wireless Propagat. Lett., Vol. 3, 340-343, 2004.
15. Bolomey, J. C. and F. E. Gardiol, Engineering Applications of the Modulated Scatterer Technique, Artech House, Norwood, MA, 2001.
16. Bolomey, J. C., B. J. Cown, G. Fine, L. Jofre, M. Mostafavi, D. Picard, J. P. Estrada, P. G. Friederich, and F. L. Cain, "Rapid near-field antenna testing via arrays of modulated scattering probes," IEEE Trans. Antennas and Propagation, Vol. 36, No. 6, 804-814, Jun., 1988.
17. Qiang, C., K. Sawaya, T. Habu, and R. Hasumi, "Simultaneous electromagnetic measurement using a parallel modulated probe array," IEEE Trans. Electomagn. Compat., Vol. 49, 263-269, 2007.
18. Jiang, J. S. and M. A. Ingram, "Spherical-wave model for short-range MIMO," IEEE Trans. Commun., Vol. 53, No. 9, 1534-1541, 2005.
19. Bohagen, F., P. Orten, and G. E. Oien, "On spherical vs. plane wave modeling of line-of-sight MIMO channels," IEEE Trans. Commun., Vol. 57, No. 3, 841-849, 2009.
20. Balanis, C. A., Antenna Theory, Analysis, and Design, 2nd Ed., Wiley, New York, 1997.
21. Mathews, C. P. and M. D. Zoltowski, "Eigenstructure techniques for 2-D angle estimation with uniform circular arrays," IEEE Trans. Signal Process., Vol. 42, No. 9, 2395-2407, Sep., 1994.
22. Du, K. L., "Pattern analysis of uniform circular array," IEEE Trans. Antennas and Propagation, Vol. 52, No. 4, 1125-1129, 2004.
23. Lazaro, A., D. Girbau, and D. Salinas, "Radio link budgets for UHF RFID on multipath environments," IEEE Trans. Antennas and Propagation, Vol. 57, No. 4, 1241-1251, 2009.
24. Azaro, R., S. Caorsi, and M. Pastorino, "On the relationship for the bistatic modulated scattering technique in scattering applications using scattering properties of antennas," IEEE Trans. Antennas and Propagation, Vol. 46, 1399-1400, Sep., 1998.
25. Lin, D. and R. Juang, "Mobile location estimation based on differences of signal attenuations for GSM systems," IEEE Trans. Vehicular Tech., Vol. 54, No. 4, 1447-1454, 2005.
26. Lin, H., S. Chen, D. Lin, and H. Lin, "Multidimensional scaling algorithm for mobile location based on hybrid SADOA/TOA measurement," IEEE Wireless Communications and Networking Conference, 3015-3020, 2008.
27. Caffery, J. J., "A new approach to the geometry of TOA location," Proc. IEEE Vehicular Tech. Conference, Vol. 4, 1943-1949, 2000.