Sample Size Considerations for Adaptive Arrays

Digital control of adaptive arrays has been shown to be a feasible alternative to analog feedback-loop control. As the eigenvalue spread of the correlation matrix no longer controls the speed of adaption, one merely has to ensure that enough samples have been taken so that the matrix estimate is close to the true matrix. While previous studies have assumed ideal conditions, it is shown here that if the true signal direction is not known exactly or if the data containing the interference are corrupted by a desired signal, then more samples are required to ensure that the estimated weighting vector gives a near optimal performance.