High Resolution DOA Estimation Using Phase Information Of MUSIC Spectrum

Direction-Of-Arrival (DOA) estimation is one of fundamental but significant techniques for high-speed mobile communication to know wave propagation environment [1]. ”Superresolution” DOA estimation methods such as MUSIC [2], Root-MUSIC [3] and ESPRIT [4] methods are paid so much attention because of their brilliant properties in estimating DOAs of incident signals. Those methods achieve very high accuracy in estimating DOAs in a good propagation environment, but would fail to estimate DOAs in severe environments like low Signal-to-Noise Ratio (SNR), small number of snapshots, or when incident waves are coming from close angles. Here we try to further improve the DOA estimation accuracy of search-based MUSIC algorithm by introducing a new concept of using phase characteristics in DOA estimation. As is well-known, MUSIC spectrum is calculated based on the absolute value of the inner product between array response vector and noise eigenvector, means that MUSIC employs only the amplitude characteristics and does not use any phase characteristics. Recalling that phase characteristics plays an important role in signal and image processing, we expect that DOA estimation accuracy could be further improved using phase characteristics in addition to MUSIC spectrum. In this paper, we develop a novel approach to DOA estimation mainly based on phase information of noise eigenbeams. The accuracy of DOA estimation is evaluated through some simulations in comparison with some representative algorithms, and we found that the proposed method achieve very high accuracy in severe environments like low SNR or incident waves coming from close angles.