Beamspace MODE

The polynomial parameterized method of direction estimation (MODE) is a popular algorithm for the direction-of-arrival (DOA) estimation of narrowband incident signals with a uniform linear array. It is desirable to apply the MODE method in beamspace so as to take advantage of the benefits of beamspace operations in terms of reduced computational complexity and improved resolution thresholds. The difficulty with beamspace MODE is that the Vandermonde structure of the array manifold may not preserve during the beamspace transformation. It is crucial to derive a parameterized polynomial in the beamspace dimension. We develop a beamspace MODE algorithm using discrete Fourier transform (DFT) beams. Our analytic study indicates that the beamspace MODE offers asymptotically statistically efficient DOA estimates. Comparative simulations are performed to demonstrate the effectiveness of the proposed beamspace MODE.