摘要
An array processing approach to joint PN (pseudo-noise) code acquisition and DOA (direction-of-arrival) estimation in asynchronous direct-sequence code-division multiple access (DS-CDMA) systems is proposed. This problem is traditionally treated as a 2-D search problem in the space-time domain. Our approach transforms the 2-D space-time matrix data from the antenna output to several time domain vectors using a set of beams steering to different directions. Then, the acquisition process searches from these 1-D temporal vectors to provide soft information for the next stage, i.e. DOA estimation. Our algorithm is a blind approach, where the training sequence is not needed. Besides, the number of antennas required can be much less than
that of the incoming signals, and the DOA search range can be largely reduced based on the soft information from the acquisition process. Numerical simulations are presented to demonstrate that the proposed solution is resistant to the near-far effect and robust to the change of the fading environment.