Statistical analysis of various wavelet functions to direction of arrival estimation

Capacity improvement techniques for cellular communication systems, such as smart antenna systems, are becoming more important as demand on mobile communication services increases. The paper analyzes the effects of different wavelet functions applied to the received signal vector by using the stationary wavelet transform (SWT) before the direction of arrival (DOA) estimation. The multiple signal classification (MUSIC) algorithm is used for the DOA estimation. Resolution of the MUSIC algorithm for uniform linear arrays decreases as the impinging signals get close to the horizon, due to the array steering vector. To enhance this poor resolution, the SWT is enhanced before the DOA estimation. Different wavelet functions affect the performance of this method, so the paper statistically analyzes these effects by simulating the received signal vector for signals arriving from close-to-horizon angles and adding a random level of noise to this vector. After the modelling of the received vector, the SWT is applied by using different wavelet functions and results are compared after 100 simulations.