A Note on The Maximum Number of Sources in DOA Estimation by MODE

This paper discusses the maximum number of sources when their direction of arrivals (DOAs) are estimated by the method of direction estimation (MODE), and presents a modified version of MODE that can estimate more number of sources than that by the original MODE. It is well-known that M-element array can basically estimate up to (M-1) DOAs, however the application of MODE may reduce up to M/2 DOAs because of its computation procedure. We propose a novel DOA estimation method by modifying MODE to employ peak-search of the primary eigenvector beam patterns instead of the null-search in the original MODE. Performance of the proposed method is evaluated through computer simulation.