Conjugate-Root Offset-QAM for Orthogonal Multicarrier Transmission

TL;DR

This paper introduces conjugate-root filters for OQAM in multicarrier systems, enabling non-symmetric filters, reducing complexity, and improving performance in GFDM and fading channels.

Contribution

It proposes non-symmetric conjugate root filters for OQAM, extending its applicability beyond band-limited symmetric filters and enhancing GFDM performance.

Findings

GFDM/CR-OQAM outperforms conventional GFDM in symbol error rate

The method reduces implementation complexity

Provides a more localized spectrum

Abstract

Current implementations of OFDM/OQAM are restricted to band-limited symmetric filters. To circumvent this, non-symmetric conjugate root (CR) filters are proposed for OQAM modulation. The system is applied to Generalized Frequency Division Multiplexing (GFDM) and a method for achieving transmit diversity with OQAM modulation is presented. The proposal reduces implementation complexity compared to existing works and provides a more regular phase space. GFDM/CR-OQAM outperforms conventional GFDM in terms of symbol error rate in fading multipath channels and provides a more localized spectrum compared to conventional OQAM.