Use of multiple antennas for DS/CDMA code acquisition

The effective use of multiple antennas is investigated for code acquisition. A generalized acquisition scheme is proposed for DS/CDMA systems with multiple antennas. The proposed scheme provides means of a trade-off between two important factors determining the mean acquisition time, which are referred to as combining gain and search time, respectively. The performance of the proposed acquisition scheme is analyzed in frequency-selective Rayleigh fading channels. In the analysis, the effects of spatial fading correlations on acquisition performance are considered. The mean acquisition time performance is evaluated for various environments, and the configuration of multiple antennas is investigated to reduce the mean acquisition time. The effects of spatial correlation on mean acquisition time are also investigated. The mean acquisition time is found to decrease significantly as the number of antenna elements increases. It is found that various parameters such as the number of antenna elements, operating signal-to-interference ratio (SIR), and the number of resolvable paths should be considered in determining configuration of multiple antennas to reduce mean acquisition time.