Speed-Sensitive Weighting Algorithm for Digital Beamforming of Adaptive Antenna Arrays

Shahriar Shirvani Moghaddam, Mahyar Shirvani Moghaddam

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DOI: 10.4236/wet.2011.23024                

Abstract

One of the main objectives of adaptive antenna array processing is reducing the computational complexity and convergence time in a joint state. This article proposes a speed-sensitive adaptive algorithm for estimating the weights of smart antenna systems based on least mean squares (LMS) or constant modulus (CM) algorithms. According to the next estimated location as well as the source velocity, this novel proposed weighting algorithm selects those weights that have a higher effect on the radiation pattern and will then form the antenna pattern by only changing these weights. In this research, 3 versions of the new algorithm named as: Not-zero (Leaves half number of weights as it is the other half), Zero (Sets half number of weights to be zero and estimates other half), and Updating (Leaves half of weights unchanged and estimates other half in one phase and updates all weights in the next phase) are proposed. Through simulation of these 3 versions of speed-sensitive algorithms and comparing among conventional full weight LMS and CM algorithms, new LMS-based and CM-based algorithms have been finally proposed that offer reduced complexity and acceptable performance at different signal to noise ratios (SNRs). In this investigation, three channel scenarios are simulated which are as follows: pure noisy channel, channel with one interferer and channel with two interferers. In accordance with the simulation results, an appropriate algorithm based on weighting half number of array elements and updating all existing weights between two consecutive times to avoid error propagation effect has been proposed.

Keywords

Beamforming, Adaptive Antenna Array, LMS, CM, Training-Based, Blind

Conflicts of Interest

The authors declare no conflicts of interest.

References

[1]	S. Ravishankar, H. V. Kumaraswamy, and B. D. Satish, “Comparative Analysis of Direction Of Arrival Estimation and Beamforming Techniques in Smart Antennas,” ObCom: Mobile, Ubiquitous & Pervasive Computing 2006 Vellore Institute of Technology Vellore, Tamil Nadu.
[2]	I. Vica Stevanovic, A. Skrivervik, and Juan R. Mosig, “Smart Antenna Systems for Mobile Communications,” Technical Report, Lab. d’Electromagn_etisme et d’Acoustique Ecole Polytechnique F_ed_erale de Lausanne, January 2003.
[3]	S. Shirvani Moghaddam, M. Shirvani Moghaddam, “A Comprehensive Survey on Antenna Array Signal Processing,” Journal of Trends in Applied Sciences Research, pp. 1-30, 2011.
[4]	J. Fuhl, E. Bonek, “Temporal Reference Algorithms versus Spatial Reference Algorithms for Smart Antennas,” Wireless Personal Communications, Vol. 9, No. 3, pp. 271-293, 1998.
[5]	S. Haykin, Adaptive Filter Theory, Prentice Hall, 1996.
[6]	T. K. Sarkar, M. C. Wicks, M. Salazar-Palma, and R. J. Bonneau, Smart Antennas, John Wiley and Sons, 2003.
[7]	C. Sun, J. Cheng, and T. Ohira, Handbook on Advancements in Smart Antenna Technologies for Wireless Networks. Idea Group Inc., Hershey, PA, 2009.
[8]	A. Bouacha, F. Debbat, and F. T. Bendimerad, “Modified Blind Beamforming Algorithm for Smart Antenna System,” Telecommunications laboratory, Faculty of Engineering, Abou-Bekr Belka?d University Tlemcen, BP 230, Algeria, January 2008.
[9]	P. C. Parini, D. X. Chen, D. J. Bigham, P. I. Liewellyn, D. L. Samuel, D. L. Ho, and B. Collins, “Final Report on Semi-Smart Antenna Technology Project,” BSC Association Ltd., 2006.
[10]	X. Sun, X. Lian, and J. Zhou, “Robust Adaptive Beamforming Based on Maximum Likelihood Estimation,” International Conference on Microwave and Millimeter Wave Technology (ICMMT 2008), pp. 1137-1140, April 2008.
[11]	R. M. Shubair, M. A. Al-Qutayri, and J. M. Sa, “A Setup for the Evaluation of MUSIC and LMS Algorithms for a Smart Antenna System,” Journal of Communications, Vol. 2, No. 4, pp. 71-77, June 2007.
[12]	Ch. Santhi Rani, P. V. Subbaiah, K. Chennakesava Reddy and S. Sudha Rani, “LMS and RLS Algorithms for Smart Antennas in a W-CDMA Mobile Communication Environment,” ARPN Journal of Engineering and Applied Sciences, Vol. 4, No. 6, pp. 77-88, August 2009.
[13]	M. Islam, Z. Rashid, “MI-NLMS Adaptive Beamforming Algorithm for Smart Antenna System Applications,” Department of Electrical, Electronics and System Engineering, Faculty of Engineering, University Kebangsaan, Malaysia, July 12, 2006.
[14]	M. Tariqul Islam, and N. Misran, “MI-NLMS Adaptive Beamforming Algorithm with Tracking Ability,” Journal of Applied Sciences, Vol. 9, Issue 12, pp. 2335-2339, 2009.
[15]	S. F. Shaukat, M. Hassan, R. Farooq, H. U. Saeed, and Z. Saleem, “Sequential Studies of Beamforming Algorithms for Smart Antenna Systems,” World Applied Sciences Journal 6, pp. 754-758, 2009.
[16]	L. Wang, R. C. Lamare, Y. L. Cai, “Low-Complexity Adaptive Step Size Constrained Constant Modulus SG Algorithms for Adaptive Beamforming,” Elsevier Signal Processing, Vol. 89, pp. 2503-2513, 2009.
[17]	L. Wang, R. C. Lamare, “Constrained Constant Modulus RLS-based Blind Adaptive Beamforming Algorithm for Smart Antennas,” 4th International Symposium on Wireless Communication Systems (ISWCS 2007), pp. 657-661, 2007.
[18]	H. Sadeghi, S. Shirvani Moghaddam, and V. Tabataba Vakili, “Appropriate CCM-based Algorithm for Adaptive Antenna Array Beamforming,” Proceedings of 5th International Symposium on Telecommunications (IST2010), Tehran, Iran, 2010.
[19]	L. C. Godara, Smart Antenna, CRC Press, 2004.
[20]	F. B. Gross, Smart Antenna for Wireless Communication with MATLAB, McGraw-Hill, 2005.
[21]	S. Shirvani Moghaddam, M. Shirvani Moghaddam, and R. Kalami Rad, “A Novel Adaptive LMS-based Algorithm Considering Relative Velocity of Source,” 7th International Symposium on Communication Systems, Networks and Digital Signal Processing (CSNDSP2010), pp. 10-14, New Castel, England, July 2010.
[22]	S. Shirvani Moghaddam, M. Shirvani Moghaddam, and R. Kalami Rad, “CMA-based Adaptive Antenna Array Digital Beamforming with Reduced Complexity,” 7th International Symposium on Communication Systems, Networks and Digital Signal Processing (CSNDSP2010), pp. 375-379, New Castel, England, July 2010.