Low-cost Turbo receiver for coded asynchronous DS-CDMA in frequency selective channels
When channel coding is used on a CDMA transmission. the most appropriate approach for reception is joint Multiuser detection and decoding. This joint problem can be successfully processed by the Turbo-techniques. Therefore, we consider a low-complexity iterative receiver for the CDMA uplink transmission, called Turbo-CDMA, and we propose to further improve it. First, we derive a new DFE to be used at the first iteration. Then, we propose to fully use the decoded information in a new structure called Full Turbo-CDMA. Finally, we derive a new demodulation order that is well suited to the Turbo-CDMA receiver. This improved receiver, called Full Turbo-CDMA, alms to eliminate MUI and ISI almost completely in the presence of frequency selective channels. Improved performance is illustrated by simulations.
turbo equalization multiuser receiver code division multiaccess (cdma) interference suppression