A spreading scheme including combined spectral and temporal spreading for OFDM systems with joint detection

Abstract

A two dimensional spreading technique for multi-antenna and multi-user OFDM systems employing joint detection is presented. In contrast to state of the art spreading techniques for OFDM systems in which typically only spreading along the frequency domain is performed, according to the scheme proposed, spreading of the user information takes place along the frequency and time domain. In this way, both frequency and time diversity inherent in the wireless channel can be exploited. Moreover, the combination of the spreading scheme proposed with joint detection yields estimates free of multiple access interference at the output of the detector.