Adaptive blind demodulation of DS/CDMA signals with transform domain Griffiths´ algorithm

The minimum mean-squared error (MMSE) linear detector has been used for demodulation of the direct-sequence code-division multiple access signals. The blind MMSE linear detector can be implemented by the Griffiths´ adaptation algorithm. However, its convergence speed is limited by the wide eigenvalue spread of the correlation matrix associated with the received signal vectors. In this paper, the transform domain Griffiths´ adaptation algorithm is proposed to improve the convergence properties. Computer simulations show that, by using orthonormal transforms, the adaptation speed can be improved, especially in the presence of strong interference