A Novel Iterative Receiver Design for CP-Free Transmission under Frequency-Selective Channels

In this letter, we develop a general iterative receiver based on the minimum mean squared error with parallel interference cancellation (MMSE-PIC) for cyclic prefix (CP)-free transmission. In particular, we consider that the receiver detects several blocks jointly, which allows backward block correction (BC). Additionally, we provide a structure with reduced complexity for Orthogonal Frequency Division Multiplexing (OFDM) and Orthogonal Chirp Division Multiplexing (OCDM) waveforms. As expected, the results show that our BC-based receiver improves the performance compared with a receiver without BC. Moreover, we show that OCDM outperforms OFDM, and has practically no performance loss compared to CP-OFDM, which motivates the use of OCDM instead of CP-OFDM to decrease latency and increase spectral efficiency.