Efficient high-resolution 3-D channel sounding

The detailed knowledge of the directional characteristics of the mobile radio channel is required to develop directional channel models and to design efficient smart antenna concepts for future mobile radio systems. In this paper, we present an efficient high-resolution scheme to estimate the dominant wavefronts in terms of their two-dimensional ar rival angles (azimuth and elevation) and their corresponding propagation delays. Here, the chip waveform of the sounding sequence and the correlation matrix of the (colored) additive noise are taken into account. To achieve these goals, 3-D Unitary ESPRIT is modified to cope with colored noise and is applied to the measurements of a uniform rectangular array in the space-frequency domain. Automatic pairing of the 3-D estimates is obtained by computing the simultaneous Schur decomposition of three real valued, non-symmetric matrices. This closed-form procedure neither requires any search nor any other heuristic pairing strategy. Due to the joint estimation of these 3-D parameters, the presented 3-D channel sounder outperforms previously proposed methods. Applications of this algorithm in direct sequence CDMA systems are also discussed briefly.