Intelligent antenna system for cdma2000

Third-generation (3G) cellular code division multiple access (CDMA,) systems can provide an increase in capacity for system operators over existing second-generation (CDMA) systems. The gain in capacity for the base station to mobile (forward) link can be attributed to improvements in coding techniques, fast power control, and transmit diversity techniques. Additional gains in the mobile to base station (reverse) link can be attributed to the use of coherent quadrature phase shift keyed (QPSK) modulation and better coding techniques. While these enhancements can improve the performance of the system, system operators expect that with increased demand for data services, even greater capacity enhancements may be desired. There are essentially three methods, which we describe, based on diversity, spatial beamforming, and a combination of diversity and beamforming, to improve the performance of system through the use of additional antennas at the base station transmitter and receiver. The performance improvements are a function of the antenna spacings and the algorithms used to weight the antenna signals. We focus on the possibilities for the cdma2000 3G system that do not require standards changes. We highlight the performance enhancements that can be obtained on both the reverse and forward links through use of an antenna array architecture that supports a combination of beamforming and transmit diversity. We focus on the performance enhancements for the forward link.

[1]  Theodore S. Rappaport,et al.  Overview of spatial channel models for antenna array communication systems , 1998, IEEE Wirel. Commun..

[2]  Siavash M. Alamouti,et al.  A simple transmit diversity technique for wireless communications , 1998, IEEE J. Sel. Areas Commun..

[3]  R. Michael Buehrer.  Generalized Equations for Spatial Correlation for Low to Moderate Angle Spread , 2002 .

[4]  R. Clarke.  A statistical theory of mobile-radio reception , 1968 .

[5]  Bernie Mulgrew,et al.  Downlink transmit diversity schemes for CDMA networks , 2000 .

[6]  Srinath Hosur,et al.  A comparison of the open loop transmit diversity schemes for third generation wireless systems , 2000, 2000 IEEE Wireless Communications and Networking Conference. Conference Record (Cat. No.00TH8540).

[7]  R. Michael Buehrer,et al.  Transmit Diversity With More Than Two Antennas , 2002 .

[8]  K. Rohani.  Open-loop transmit diversity for CDMA forward link , 2000, 2000 IEEE Emerging Technologies Symposium on Broadband, Wireless Internet Access. Digest of Papers (Cat. No.00EX414).

[9]  M. Skolnik,et al.  Self-phasing array antennas , 1964 .

[10]  Bengt Lindoff,et al.  Channel estimation for the W-CDMA system, performance and robustness analysis from a terminal perspective , 1999, 1999 IEEE 49th Vehicular Technology Conference (Cat. No.99CH36363).

[11]  Markku Renfors,et al.  Robustness of practical downlink wideband CDMA channel estimation algorithms to delay estimation errors , 2001, ICC 2001. IEEE International Conference on Communications. Conference Record (Cat. No.01CH37240).

[12]  Anand G. Dabak,et al.  The use of iterative channel estimation (ICE) to improve link margin in wideband CDMA systems , 1999, 1999 IEEE 49th Vehicular Technology Conference (Cat. No.99CH36363).

[13]  Arogyaswami Paulraj,et al.  Space-time processing for wireless communications , 1997 .

[14]  Andrea M. Tonello,et al.  Spatial channel model and measurements for IMT-2000 systems , 2001, IEEE VTS 53rd Vehicular Technology Conference, Spring 2001. Proceedings (Cat. No.01CH37202).