Fast-ICA Based Blind Estimation of the Spreading Sequences for Down-link Multi-Rate DS/CDMA Signals

This paper deals with the problem of blind estimation of the spreading sequences in multi-rate direct-sequence code division multiple access(DS-CDMA). The characteristic of the down-link Multi-Rate DS/CDMA signal is analyzed, and the down-link Multi-Rate DS/CDMA signal is modeled as the blind source separation pattern at first. Then an efficient iterative dimension-increased method based Fast-ICA algorithm, from small spreading period to bigger spreading period, is exploited to estimate the whole or part of period spreading sequences blindly, the 2-norm of vectors is employed to separate spreading sequence which with different spreading period, and obtain all users´ spreading sequence blindly at lastly. Mathematical analysis and simulation results demonstrate the validity of the new method.