Combining Antenna Array Elements by Using ICA Method for Remote Sensing of Sources

Abstract

This letter deals with the problem of determining the number of RF sources faced by wireless communication systems. In presence of several sources, it is unavoidable to have signal superposition, loss of tracking, and degrading (ambiguous) estimation. Moreover, the well-known subspace-based methods for tracking and estimating sources require prior knowledge of the number of sources. It is shown here that the independent component analysis (ICA) method can be used not only to determine the number of sources, but also to increase the number of sensors (measures) by combining the array elements. The results also show that narrowband sources having a very small frequency difference $(\mathbf{\Delta F} = \mathbf{0.41}\%)$ are detected. The ICA ability of blind sources separation makes it suitable to determine the number of unknown sources, which is crucial in subspace-based techniques. For instance, the ICA can be used as preprocessing model order estimation in direction of arrival algorithms for smart antenna systems.