Acquisition Behavior of Some Adaptive Arrays
The performance of two adaptive array schemes is analyzed. In scheme A, the desired signal is specified by a beam-forming vector; in scheme W, by a known pilot signal. In a stationary interference environment, if loop gains are high enough and the effective time constants are long enough, the weights in both systems will converge to values for which the output signal-to-interference ratio is maximum. One result of the analysis is a criterion for choosing loop gain and time constants that should be useful in designing an automatic gain control system, a practical necessity for both schemes. For the A scheme, the output signal-to-interference enhancement history during adaptation is found under the assumption that smoothing is sufficient to make weight fluctuations small and slow. For the W scheme, settling time varies inversely with pilot-to-interference power ratio. The results presented in this report are for the narrowband case.