Beam‐space CMA adaptive array antennas

In the communication system using a constant modulus signal, a constant modulus algorithm (CMA) adaptive array antenna is effective for elimination of the frequency-selective fading generated in multiple propagation paths. On the other hand, in the system in which CMA adaptive loops are installed for each antenna element in an array with more than 10 elements used for mobile satellite communication, the computing time and the amount of hardware become excessive. In this paper, a beam-space CMA adaptive array antenna (BSCMA) is proposed in which a portion of the multibeam output is selected to form a CMA adaptive array. In the BSCMA, first, a multibeam is formed by means of a fast Fourier transform (FFT) and only the beams whose output power exceeds a threshold level are selected. an adaptive process is carried out with the CMA as a guiding principle only for the selected beam outputs. the BSCMA has an advantage of carrying out the capture of the desired wave and the elimination of the interference wave effectively with degrees of freedom corresponding to the number of arriving waves. the method is effective for an adaptive antenna system applied to an array antenna constructed with many antenna elements. In this paper, the configuration of the BSCMA is shown and its characteristics are investigated by the numerical simulation.