A variable rate multi-user CI/GO-OFDMA scheme over frequency selective channel

Abstract

In this paper, we present Carrier Interferometry (CI) spread OFDMA system with orthogonal subcarrier grouping (CI/GO-OFDMA) to support variable rate user classes. This work highlights the application of CI codes which can be generated for any integer to ensure efficient multicarrier variable rate transmission scheme. Simulation results obtained over pedestrian channel clearly shows that BER performance of CI based GO-OFDMA scheme significantly outperforms VSL MC-CDMA variable rate scheme for four different data rate users. CI codes with GO-OFDMA also ensures low peak to average power ratio (PAPR) and at the same time comparable complexity compared to VSL MC-CDMA. Further Pseudo Orthogonal Carrier Interferometry (PO-CI) codes can be used to support additional users/data rates which increases the spectral efficiency.