Analysis of the performance of adaptive beamforming using perturbation sequences

Conventional adaptive antenna array processing employing gradient descent requires access to signals on all the antenna array elements. The processing can be carried out at the radio frequency stage, an intermediate frequency stage, and in some cases at baseband. In all cases coherence of the array element signals must be maintained. For situations where access to all the array channels is not possible or not economical, a new technique for adaptively controlling the array weights has been developed. The technique requires access to the controllable weights and the beam-former output. Detailed analysis of the performance of the technique has been carried out. A number of possible structures which can be used are briefly reviewed, and the results of analysis of the performance achievable with some of these structures are presented. A detailed comparison of the performance of the new technique with that of a system in which all signals are available is given. Ways of optimizing the performance of the new technique are considered. Results of computer studies of the performance of the new technique are presented.