An approach to blind estimation of OVSF sequence in weak WCDMA signals

For the problem of the WCDMA uplink signals to blindly estimate the Orthogonal Variable Spreading Factor (OVSF) code sequence in low signal to noise ration (SNR), this paper proposed an approach that is developed using correlation matrix accumulation and singular value decomposition. The parameters of the WCDMA signals (such as the period and chip interval of the OVSF sequence) need to be known. The received signals are divided into multiple continuous observation vectors based on the OVSF sequence period with the fixed value as the starting point. Then combining the accumulation and eigen-analysis of correlation matrix, and the OVSF sequence of the WCDMA signals is blindly estimated from the main component eigenvector. Then the WCDMA signals can be despreaded with the OVSF sequence. The simulation experiments show the method can work well in lower SNR environments.