An approach for improving signal to interference plus noise ratio in MC DS-CDMA downlink system

Abstract

Transmitter based linear precoding scheme that outperforms conventional precoding by making use of a portion of the interference between the users in a multicarrier direct sequence code-division multiple-access (MC DS-CDMA) system downlink is proposed. A part of interference utilization is achieved by selectively orthogonalizing the desired symbols to destructive interference by means of precoding while allowing interference that constructively contributes to the useful signal's energy. Existence and exploitation of constructive interference effectively spreads the signal constellation and enhances the signal-to-interference-plus-noise ratio (SINR) at the receiver. The scheme introduced in this project applies to the downlink of cellular phase-shift keying (PSK)-based MC DS-CDMA systems. © 2013 Springer-Verlag.