Cramer-Rao bounds for the estimation of multipath parameters and mobiles' positions in asynchronous DS-CDMA systems

Commercial applications for the location of subscribers of wireless services continue to expand. Consequently, finding the Cramer-Rao lower bound (CRLB), which serves as an optimality criterion for the location estimation problem, is of interest. In this paper, we derive the deterministic CRLBs for the estimation of the specular multipath parameters and the positions of the mobiles in an asynchronous direct sequence code division multiple access (DS-CDMA) system operating over specular multipath fading channels. We assume a multilateral radio location system where the location estimates are obtained from some or all of the estimated signal parameters at different clusters of antennas of arbitrary geometry. Extension for unilateral and composite radio location techniques is also discussed. As an application example, we use numerical simulations to investigate the effects of specular multipath and multiple access interference (MAI) on the positioning accuracy for different radio location techniques.

[1]  J. Chaffee,et al.  GDOP and the Cramer-Rao bound , 1994, Proceedings of 1994 IEEE Position, Location and Navigation Symposium - PLANS'94.

[2]  Kung Yao,et al.  Direct joint source localization and propagation speed estimation , 1999, 1999 IEEE International Conference on Acoustics, Speech, and Signal Processing. Proceedings. ICASSP99 (Cat. No.99CH36258).

[3]  Arogyaswami Paulraj,et al.  Estimation of multipath parameters in wireless communications , 1998, IEEE Trans. Signal Process..

[4]  Shirley Dex,et al.  JR 旅客販売総合システム（マルス）における運用及び管理について , 1991 .

[5]  W. Rudin.  Principles of mathematical analysis , 1964 .

[6]  A. Host-Madsen,et al.  Statistical theory of the effects of radio location system design parameters on the positioning performance , 2002, Proceedings IEEE 56th Vehicular Technology Conference.

[7]  Yoram Bresler,et al.  A compact Cramer-Rao bound expression for parametric estimation of superimposed signals , 1992, IEEE Trans. Signal Process..

[8]  Stefan Parkvall,et al.  DS-CDMA Synchronization in Time-Varying Fading Channels , 1996, IEEE J. Sel. Areas Commun..

[9]  James J. Caffery,et al.  Wireless Location in CDMA Cellular Radio Systems , 1999 .

[10]  J. Holtzman,et al.  The non-line of sight problem in mobile location estimation , 1996, Proceedings of ICUPC - 5th International Conference on Universal Personal Communications.

[11]  Erik G. Ström,et al.  A maximum likelihood approach for estimating DS-CDMA multipath fading channels , 2000, IEEE Journal on Selected Areas in Communications.

[12]  H. Koshima,et al.  Personal locator services emerge , 2000 .

[13]  Gregory G. Raleigh,et al.  Joint space-time parameter estimation for wireless communication channels , 1998, IEEE Trans. Signal Process..

[14]  M. Hata,et al.  Empirical formula for propagation loss in land mobile radio services , 1980, IEEE Transactions on Vehicular Technology.

[15]  S. Kay.  Fundamentals of statistical signal processing: estimation theory , 1993 .

[16]  Theodore S. Rappaport,et al.  Smart Antennas for Wireless Communications: Is-95 and Third Generation Cdma Applications , 1999 .

[17]  Mati Wax,et al.  Joint estimation of time delays and directions of arrival of multiple reflections of a known signal , 1996, 1996 IEEE International Conference on Acoustics, Speech, and Signal Processing Conference Proceedings.

[18]  Hongya Ge,et al.  Joint space-time channel parameter estimation for DS-CDMA system in multipath Rayleigh fading channels , 2001 .

[19]  Theodore S. Rappaport,et al.  An overview of the challenges and progress in meeting the E-911 requirement for location service , 1998, IEEE Commun. Mag..

[20]  Petre Stoica,et al.  MUSIC, maximum likelihood, and Cramer-Rao bound , 1989, IEEE Transactions on Acoustics, Speech, and Signal Processing.

[21]  Anders Høst-Madsen,et al.  Cramer-Rao bound for location estimation of a mobile in asynchronous DS-CDMA systems , 2001, 2001 IEEE International Conference on Acoustics, Speech, and Signal Processing. Proceedings (Cat. No.01CH37221).

[22]  Anders Høst-Madsen,et al.  Effects of system and environment parameters on the performance of network-based mobile station position estimators , 2004, IEEE Transactions on Vehicular Technology.

[23]  K. C. Ho,et al.  A simple and efficient estimator for hyperbolic location , 1994, IEEE Trans. Signal Process..

[24]  Jeffrey H. Reed,et al.  Position location using wireless communications on highways of the future , 1996, IEEE Commun. Mag..

[25]  Constantinos B. Papadias,et al.  Joint angle and delay estimation (JADE) for multipath signals arriving at an antenna array , 1997, IEEE Communications Letters.