Linear multiuser detector update in synchronous dynamic CDMA systems

For synchronous CDMA systems the decorrelating multiuser detector is the inverse of the correlation matrix of the signature waveforms. The noise-whitening multiuser detector is the inverse of the Cholesky factor of the correlation matrix. If the number of users or the signature signals changes, the detectors must be recomputed. The paper introduces order-recursive algorithms for detector update. The algorithms compute either the inverse or the Cholesky factorization of the correlation matrix. The numerical accuracy of the algorithms is found to be superior even with random spreading sequences