Direct-sequence spread-spectrum using directionally constrained adaptive beam forming to null interference

A direct-sequence spread-spectrum communication system using an adaptive antenna array to null interference is examined. The system model is a modification of Compton´s (1978) system, using a digital implementation and a directional constraint. Computer simulations are used to compare the behavior of the directionally constrained model with Compton´s model with emphasis on spread-spectrum code synchronization. In the directed system, nulling of a tone jammer occurs without respect to direct-sequence code acquisition, and nulling of an off-beam desired signal occurs very slowly. Theoretical results are obtained by using the system covariance matrix, and incorporating the effects of spread-spectrum filtering to compute the system response as a function of time. The simulated results indicate that incomplete directional knowledge may be exploited to enhance signal quality and speed up code acquisition