A simple method for computing partial cancellation factors in CDMA using PPIC receiver

A new closed-form expression for the partial cancellation factor (PCF) in a multistage partial parallel interference cancellation (PPIC) receiver is introduced. This approach has several advantages compared to a previously proposed method. First of all, PCFs are found directly from the moments of the eigenvalues of the correlation matrix. This results in less complexity in circuitry. In addition, there is no need that the PCFs be ordered. Therefore, a monotonically improving performance is obtained with even more reduced complexity. Finally, it is not necessary to know the number of interference cancellation stages a priori. It is shown that by choosing these PCFs, the performance of PPIC receiver converges to that of the minimum mean-squared error (MMSE) receiver.