A new simultaneous estimation of directions of arrival and channel parameters in a multipath environment

We present two new blind techniques for simultaneous estimation of the direction-of-arrival (DOA) and the channel parameters for a uniform linear array in a multipath environment. The first method is based on the sum of weighted complex exponentials and Pade´ approximation, and the second method determines the transfer function of a linear time-invariant system given its impulse response. For each method, we introduce a rational function whose complex poles contain the desired DOA, the magnitude of its residues are the channel gains, and the phase of its residues are in terms of the channel delays. We also derive and numerically evaluate the pertinent Crame´r-Rao lower bound (CRLB) for the estimation process. Our error analysis based on a perturbation series formulation of the parameter estimation reveals that DOA and the channel parameters are extracted from a Gaussian signal-dependent noise. For both methods, the amount of computations are also determined. Some simulations are provided to assess the capabilities of the new methods.