BEAM-SPACE CMA ADAPTIVE ARRAY ANTENNAS

In the communication system using a constant modulus signal, a constan t modulus algorithm (CMA) adaptive array antenna is effective for elim ination of the frequency-selective fading generated in multiple propag ation paths. On the other hand, in the system in which CMA adaptive lo ops are installed for each antenna element in an array with more than 10 elements used for mobile satellite communication, the computing tim e and the amount of hardware become excessive. In this paper, a beam-s pace 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 tra nsform (FFT) and only the beams whose output power exceeds a threshold level are selected. An adaptive process is carried out with the CMA a s a guiding principle only for the selected beam outputs. The BSCMA ha s an advantage of carrying out the capture of the desired wave and the elimination of the interference wave effectively with degrees of free dom corresponding to the number of arriving waves. The method is effec tive for an adaptive antenna system applied to an array antenna constr ucted with many antenna elements. In this paper, the configuration of the BSCMA is shown and its characteristics are investigated by the num erical simulation.