Minimum Variance Distortionless Response Technique Research Articles

Performance Comparison of Nature-Inspired Optimization Algorithms Applied to MVDR Technique for Canceling Multiple Access Interference Signals

Background/Objectives: Minimum Variance Distortionless Response (MVDR) beam forming technique is among the most widely used in antenna array field. The conventional MVDR has poor performance, and low Signal to Interference plus Noise Ratio (SINR) gain in the condition of limited snapshots or Multiple Access Interference (MAI) signals existing. Heuristic optimization algorithms are broadly used to solve many engineering problems. Methods/Analysis: In this work, two nature-inspired optimization methods, namely Particle Swarm Optimization (PSO) and Gravitational Search Algorithm (GSA) are applied to enhancing the conventional MVDR performance. In particular, the complex weight coefficients of the conventional MVDR solution are improved using both approaches. First, SINR calculated from MVDR basing linear antenna array configuration then the PSO and GSA implemented to minimizes the power of noise and interference in the constraint condition. The performance of the proposed methods is assessed based on various QoS criteria such as beampattern accuracy for azimuth and elevation scanning angles and SINR output. Findings: In comparison to conventional MVDR, the proposed algorithms have indicated that MVDRGSA providesfavorable agreement of synthesizing a maximum gain toward the desired real user angle while introducing deep null-forming in the undesired user directions. As a result, average SINR is evaluated over 20 runs in all simulation scenarios, the performance of MVDRGSA is better than the performance of MVDRPSO. Moreover, a good control over the null-forming level can be achieved by MVDRGSA for iteration number < 100 whereas MVDRPSO is simple and easy to implement but required more convergence time to get high SINR. Application/Improvements: In general, it was observed that MVDRGSA out performs the MVDRPSO with respect to solution quality, stability and convergence speed. Keywords: Beam Forming, Linear Antenna Array, Smart Antenna, GSA, MVDR, PSO, SINR

On the alternative objective functions for minimum variance distortionless response technique in order to restore the original source

Minimum Variance Distortionless Response (MVDR) technique is one of the signal processing ways for noise reduction. Its principle is to minimize the output power of the signal. This study simulated an underwater acoustic field using ray acoustic method. The acoustic field consists of a signal source, multiple noise sources and a line array hydrophones. The signal source is ship-radiated noise. The simulated combining signals received by the hydrophone array are used to restore the original signal source by MVDR technique. The study discusses the different objective functions given in MVDR in order to restore the original source. Then, the results are compared in computing time, effectiveness and adaptability. The results indicate that MVDR can be used to restore the original signal source with very high correlation coefficient up to 90% between the original signal and the restored one.

Application of time reversal mirror and minimum variance distortionless response technique for source localization

Time difference of arrival (TDOA) and time reversal mirror (TRM) are commonly used in acoustic source localization. TDOA has excellent results in free field, but fair results in multiple reflections environment. TRM is applicable in multiple reflections environment and for multiple sources localization. The study continues the advantage of TRM and combines MVDR technique of noise reduction in order to find source locations. The results indicate that the combined MVDR technique gives better noise reduction than TRM in multiple reflections environment. From the drawing of energy diagram of acoustic waveguide, the combined MVDR technique will focus energy on signal source and it also reduces the noise energy in the other region. Comparing between TRM and the combined MVDR for source localization, the combined MVDR gives better resolution than TRM does. In addition to give better resolution, the combined MVDR will find the source location by finding the maximum energy location, on the other hand, TRM is unabl...