Shift invariance algorithms for the angle/delay estimation of multipath space-time channel

In time-division CDMA systems the angle/delay of the multipath propagation channel can be estimated jointly by exploiting the invariance of angles/delays across multiple slots regardless of fast-variation in faded amplitudes. The joint angle/delay estimation (JADE) is reduced to the estimation of frequency of 2D sinusoids, here the shift-invariance method (2D-ESPRIT) is used. Application of JADE to 3^rd generation mobile communication system (TDD-UTRA standard) and to realistic propagation environments demonstrates the advantage of the proposed method. Linear multiuser detection that exploits angle/delay estimates shows a meaningful improvement (approx. 2÷4 dB in signal to noise ratio) with respect to the conventional least square estimate