Systolic implementation of the steepest descent algorithm and its performance in CDMA receivers

In code division multiple access receivers, in order to suppress the multiple access interference, different multiuser detectors such as the decorrelating and the linear minimum mean square error detectors can be utilized. In order to alleviate the implementation complexity, iterative implementation of such detectors have been reported. Two most popular iterative algorithms used in such detectors are the Steepest Descent (SD) and the Conjugate Gradient (CG) algorithms. In this paper, we first compare fixed-point and floating-point performances of these algorithms. Furthermore, hardware implementations of the algorithms are compared. Based on these comparisons, for the implementation of the SD algorithm a systolic architecture is proposed.