Direction of Arrival Estimation and Beamforming of Multiple Coherent UWB Signals

In This paper we have addressed the problem of direction of arrival (DOA) estimation algorithm and beamforming for Impulse Radio (IR) Ultra-wideband (UWB) communication systems in additive white Gaussian noise. The multi user UWB pulse-position modulation (PPM) signals are received by smart antenna(Uniform linear array) are Fourier transformed to split the array output into multiple frequency channels, and the corresponding indexed bin data arranged in the form of polynomial model. On this Iterative quadratic maximum likelihood (IQML) algorithm is applied to yield DOA estimates. These DOA estimates at different frequencies are combined into a single estimate in an averaging manner. After obtaining a frame work for DOA estimation we turn our attention to beamforming. Interference-plus-noise subspace characterized and DOA´s of the interference signals are exploited to estimate signal free covariance matrix and weight vector is developed to maximize the signal -to- interference-plus noise ratio (SINR) at the output of the beamformer. The performance of the proposed method is studied via extensive computer simulations.