Two-dimensional code acquisition using antenna arrays

An extension of conventional (delay domain) code acquisition to the delay-angle domain is studied. The two-dimensional uncertainty region is serially searched in an angle-delay or delay-angle fashion. Under the assumption that the signal is seen from one out of m possible angular directions and the interference can be modeled as temporarily and spatially white we show that there exist an optimum number of angular cells for which the mean acquisition time can be minimized. This optimum number of angular cells m is a function of the prevailing signal-to-noise ratio. The best performance is found for the case of the optimum threshold but nearly as good figures can be obtained with constant false alarm rate schemes.