An Empirical Method for Estimating the Number of Signal Sources

In this paper we propose an empirical method for estimating the number of sources of signals impinging on multiple sensors. The method is based on the analysis of the norms of vectors whose elements are the normalized eigenvalues of the received signal covariance matrix and the corresponding normalized indexes. It is shown that such norms can be used to classify the eigenvalues in two groups: the largest and the remaining ones, thus allowing for the estimation of the number of sources without the knowledge of any additional parameter. It is shown that, in some situations, our norm-based method produces satisfactory performance when compared to a recently proposed random matrix theory method.