A novel adaptive beamforming algorithm for antenna array CDMA systems with strong interferers

Blind beamforming based on the maximum signal-to-noise ratio (MSNR) can improve the performance of an array system only when the processing gain of the given code-division multiple-access (CDMA) system is high enough such that the desired signal can become dominant after despreading (see Choi, S. and Shim, D., IEEE Trans. Veh. Technol., vol.49, p.1793-1806, 2000; Choi, S. and Yun, D., IEEE Trans. Antennas Propagat., vol.45, p.1393-1404, 1997). We consider a maximum signal-to-interference-plus-noise ratio (MSINR) beamforming. The MSINR performance criterion is chosen to deal with strong interferers effectively. It is shown that blind MSINR beamforming is possible by directly utilizing the input and output signals of correlators of the CDMA systems. In addition, we propose an adaptive beamforming algorithm at a lower computational complexity - about O(7.5N) - where N is the number of antenna elements of the array system. Simulation results are presented in various signal environments to show the performance of the proposed adaptive algorithm.

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

[2]  Boon Chong Ng,et al.  Space-time modems for wireless personal communications , 1998, IEEE Wirel. Commun..

[3]  Arogyaswami Paulraj,et al.  Performance of CDMA mobile communication systems using antenna arrays , 1993, 1993 IEEE International Conference on Acoustics, Speech, and Signal Processing.

[4]  W. C. Jakes,et al.  Microwave Mobile Communications , 1974 .

[5]  Erik Dahlman,et al.  WCDMA-the radio interface for future mobile multimedia communications , 1998 .

[6]  Jinho Choi.  Pilot channel-aided techniques to compute the beamforming vector for CDMA systems with antenna array , 2000, IEEE Trans. Veh. Technol..

[7]  George V. Tsoulos,et al.  On the application of adaptive antennas to microcellular environments: radio channel characteristics and system performance , 2002, IEEE Trans. Veh. Technol..

[8]  Ayman Fawzy Naguib,et al.  Adaptive antennas for CDMA wireless networks , 1996 .

[9]  Fumiyuki Adachi,et al.  Wideband DS-CDMA for next-generation mobile communications systems , 1998, IEEE Commun. Mag..

[10]  Seungwon Choi,et al.  A novel adaptive beamforming algorithm for a smart antenna system in a CDMA mobile communication environment , 2000, IEEE Trans. Veh. Technol..

[11]  Sergio Verdu,et al.  Multiuser Detection , 1998 .

[12]  Leonard E. Miller,et al.  NASA systems engineering handbook , 1995 .

[13]  Jack H. Winters,et al.  Smart antennas for wireless systems , 1998, IEEE Wirel. Commun..

[14]  R.C. Johnson,et al.  Introduction to adaptive arrays , 1982, Proceedings of the IEEE.

[15]  Seungwon Choi,et al.  Design of an adaptive antenna array for tracking the source of maximum power and its application to CDMA mobile communications , 1997 .