High-throughput high-performance OFDM via carrier interferometry approaches for complex signaling

Carrier Interferometry (CI) approaches, including Carrier-Interferometry Orthogonal Frequency Division Multiplexing (CI/OFDM) and Pseudo-Orthogonal Carrier-Interferometry OFDM (PO-CI/OFDM), have been proposed to enhance OFDM’s performance and reduce OFDM’s peak-to-average power ratio (PAPR). However, the existing high-throughput, high-performance PO-CI/OFDM system is limited for real signaling. This paper first proposes to use Inverse Fast Fourier Transform (IFFT)/Fast Fourier Transform (FFT), instead of vector-matrix multiplication, to implement the spreading/despreading in CI/OFDM and PO-CI/OFDM. Secondly, PO-CI/OFDM system is proved not applicable for complex signaling. Based on the analysis of CI spreading codes, PO-CI spreading codes and CI/OFDM system, a novel OFDM system architecture, named CI-POCI/OFDM, is introduced to provide double-throughput, high-performance for complex signaling. Furthermore, PAPR problem of traditional OFDM is also eliminated in CI-POCI/OFDM system.