Direct blind symbol estimation for DS-CDMA without channel estimation

Based on the subspace method, a closed-form CDMA signal and DOA estimation approach without the knowledge of space-time channel and training sequence is presented in this paper. An auxiliary matrix is constructed by exploiting the special structure of the antenna array. Then the symbols instead of their signal subspace are achieved by eigen decomposition of the auxiliary matrix. Therefore, the puzzle of separating the different users' signal from their signal subspace in conventional blind symbol estimation method is avoided. In comparison with conventional space-time linear multiuser detector, in which the knowledge of space-time channel is assumed to be known, the proposed method has the advantage of lower computation without degrading the near-far resistance performance. Finally, numeral simulations are presented.