A novel DS-CDMA direction of arrival estimator for frequency-selective fading channel with correlated multipath by using beam forming filter

In this paper a new method for estimating the direction of arrival of Asynchronous DS-CDMA signals is proposed. In this method we have assumed to have a frequency-selective fading channel with correlated multipath. In the proposed method first for removing effects of undesired paths we apply the coherent signals of the undesired paths perpendicularly to the under process signal, next, signal is passed through a filter bank and then using the “beam space” idea direction of signal is discovered. Since beam forming filters are used, effects from other users on the desired users signal is also decreased which in turn increase the efficiency of the algorithm and search area decrease almost to one tenth. In this algorithm it is not required to search all angles as in conventional methods like MUSIC. Besides, this algorithm does not require information criteria like minimum description length minimum description length (MDL) and Akaike's information criterion (AIC) for estimating the number of sources. Another advantage of this method is that number of users can exceed the number of antenna arrays contrary to many of the conventional methods. At the end, some simulation results are illustrated to confirm the efficiency of the method.