On the design of frequency-domain equalizers for OQPSK modulations

This paper considers frequency-domain receiver design for OQPSK signals (Offset Quaternary Phase Shift Keying). It is shown that conventional QPSK receivers are not suitable to OQPSK schemes since they lead to significant interference between in-phase (I) and quadrature (Q) components. To overcome this problem we propose several linear receivers where there is no I-Q interference. Our receivers are suitable to OQPSK schemes, significantly outperforming frequency-domain receivers designed for QPSK modulations.