DECORRELATING DECISION-FEEDBACK MULTIUSER DETECTOR FOR SYNCHRONOUS CODE-DIVISION MULTIPLE-ACCESS CHANNEL

Several multiuser detectors for code-division multiple-access (CDMA) systems have been studied recently. We propose a new decorrelating decision-feedback detector (DF) for synchronous CDMA which utilizes decisions of the stronger users when forming decisions for the weaker ones. The complexity of DF is linear in the number of users, and it requires only one decision per user. Performance gains with respect to the linear decorrelating detector are more significant for relatively weak users, and the error probability of the weakest user approaches the single-user bound as interferers grow stronger. The error rate of DF is compared to those of the decorrelator and the two-stage detector.