DOA Tracking in Multipath Environment based on the Direction Lock Loop

Smart antenna technology is strong candidate for the evolution of multiple access systems. Implementation of this technology for real-time operation is a challenge for adaptive signal processing algorithms. Deterministic algorithms that depend on snapshot-by-snapshot processing are suitable for facing this challenge due to their relatively low computational requirements. The Direction Lock Loop, DiLL, is a deterministic algorithm that iteratively tracks the DOA of fast moving sources in CDMA environment. The main limitation of the DiLL is that it cannot deal with coherent multipath situations. In this paper, that limitation is overcome, and the DiLL is employed in a deterministic smart antenna processor for DOA tracking in coherent multipath environment. The proposed system can be implemented FDMA/TDMA as well as CDMA cellular networks. The validity of the proposed method is tested using computer simulations.