Initial Code Acquisition in the Cooperative Noncoherent MIMO DS-CDMA Downlink

In this paper, we investigate a realistic code-acquisition-assisted cooperative noncoherent (NC) multiple-input-multiple-output (MIMO) direct-sequence code-division multiple-access (DS-CDMA) downlink scenario, when communicating over uncorrelated single- and multipath Rayleigh channels. The probabilities of correct detection and false alarm have analytically been derived. Furthermore, a mean acquisition time (MAT) formula is provided for the cooperative transmission scenario considered. The associated MAT performance trends are characterized as a function of both the number of relay stations (RSs) and the number of receive antennas and link imbalance. As opposed to the classic scenario of having colocated MIMO elements, our findings suggest that employing distributed MIMO elements acting as RSs combined with multiple receive antennas leads to an improved MAT performance.