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.