A Study on MVDR Beamforming Applied to an ESPAR Antenna

The adaptive beamforming algorithm-minimum variance distortionless response (MVDR) has been studied based on the electronically steerable parasitic array radiator (ESPAR) antenna. The ESPAR antenna uses a single radio-frequency (RF) front end, and its beamforming is achieved by adjusting reactance loads of parasitic elements coupled to the central active element. In the proposed beamforming method, the MVDR beamformer optimizes weights applied to outputs of beams. The optimization problem is formulated as a second-order-cone programming (SOCP) problem including a Euclidean distance metric to approximate the optimal equivalent weight vector to a feasible solution. Then the ESPAR beampattern design strategy iterates between the SOCP problem and a simple projection of reactance loads. The simulations show that the proposed MVDR beamforming method based on an ESPAR antenna gives a beam steering at the desired direction and placing nulls at the interfering directions, and it converges fast. However, when the desired source is close to the interferer, the output signal-to-interference-plus-noise ratio (SINR) degrades and where we use the interference-plus-noise sample covariance matrix to improve the beamforming performance.

[1]  T. Ohira,et al.  Fast beamforming of electronically steerable parasitic array radiator antennas: theory and experiment , 2004, IEEE Transactions on Antennas and Propagation.

[2]  Tharmalingam Ratnarajah,et al.  On Spatial Domain Cognitive Radio Using Single-Radio Parasitic Antenna Arrays , 2013, IEEE Journal on Selected Areas in Communications.

[3]  Johan Löfberg,et al.  YALMIP : a toolbox for modeling and optimization in MATLAB , 2004 .

[4]  L. C. Godara,et al.  Applications Of Antenna Arrays To Mobile Communications, Part I: Performance Improvement, Feasibility, And System Considerations , 1997, Proceedings of the IEEE.

[5]  T. Ohira,et al.  Reactance-domain ESPRIT algorithm for a hexagonally shaped seven-element ESPAR antenna , 2005, IEEE Transactions on Antennas and Propagation.

[6]  V. Barousis,et al.  A Stochastic Beamforming Algorithm for ESPAR Antennas , 2008, IEEE Antennas and Wireless Propagation Letters.

[7]  Mathini Sellathurai,et al.  Performance of the blind interference alignment using ESPAR antennas , 2013, 2013 IEEE International Conference on Communications (ICC).

[8]  T. Ohira,et al.  Reactance domain MUSIC algorithm for electronically steerable parasitic array radiator , 2004, IEEE Transactions on Antennas and Propagation.

[9]  Henry Cox,et al.  Robust adaptive beamforming , 2005, IEEE Trans. Acoust. Speech Signal Process..

[10]  T. Ohira,et al.  Electrically steerable passive array radiator (ESPAR) antennas , 2005, IEEE Antennas and Propagation Magazine.

[11]  I. N. Psaromiligkos,et al.  Interference-plus-noise covariance matrix estimation for adaptive space-time processing of DS/CDMA signals , 2000, Vehicular Technology Conference Fall 2000. IEEE VTS Fall VTC2000. 52nd Vehicular Technology Conference (Cat. No.00CH37152).