Performance of transmitter preprocessing aided cooperative downlink MC-DS-CDMA system

In this article, we revisit the performance of a downlink (DL) multi-carrier direct-sequence code-division multiple-access (MC-DS-CDMA) system when the destination mobile stations (DMSs) are aided by a group of relay stations for achieving the relay diversity. In our work, transmitter preprocessing is invoked at the base-station (BS) as well as at the relay stations to suppress the DL multi-user interference (MUI) and the inter-relay interference (IRI) at the relays and the DMSs, respectively. In particular, we investigate the achievable bit error rate (BER) performance of the relay aided MC-DS-CDMA downlink communication with transmitter preprocessing. Our study shows that the transmitter preprocessing efficiently mitigates the MUI at the relays and IRI at the DMSs, thereby significantly contributing to achieve the relay diversity. Further, the preprocessing approach results in low-complexity signal processing at the relay stations in the context of signal detection.