An improved cyclic adaptative beamforming (CAB) algorithm for a multiple agile beam mobile communication system

The use of multiple high gain agile beams from a multiple element array antenna with on-board digital beamforming is being considered in the next generation of mobile satellite communication systems. A blind adaptive beamforming algorithm is presented which improves the performance of the CAB. Noting that the weighting vectors of the CAB are not in general proportional to the signal steering vectors in the case of multiple signals, a singular vector rotation technique is used to iteratively estimate the steering vectors. Using the estimated steering vectors as the constraint matrix in the LCMV algorithm, better interference suppression is achieved. Computer simulations are conducted to demonstrate that the performance of the proposed algorithm is superior to that of the CAB for the scenario of multiple co-channel users transmitting at the same frequency