A Cyclic Prefix-Free OFDM System Based on Iterative Extrapolation: Design and Performance Analysis

The Cyclic prefix (CP) in traditional OFDM systems is used to combat inter-symbol Interference (ISI) and inter-carrier Interference (ICI), which simplifies the design of the equalizer by converting the linear convolution (LS) between symbols and the channel into cyclic convolution (CC). However, the overhead of CP reduces the system’s spectral efficiency and energy efficiency. This paper proposes a CP-free OFDM system called TSE-OFDM by exploiting a truncated symbol extrapolation (TSE) module. The TSE module categorizes the received OFDM symbols into reliable and unreliable parts based on their susceptibility to ISI. By iteratively extrapolating the reliable portion unaffected by ISI, the TSE module restores the CC characteristic of the received symbols. We conduct noise analysis and simulations to evaluate the performance of the extrapolation algorithm, demonstrating its robustness against out-of-band noise. Furthermore, we simulate the TSE-OFDM system to assess its bit error rate (BER) and spectral efficiency (SE). The simulation results show that TSE-OFDM significantly improves SE while maintaining satisfactory BER performance. Compared to other CP-free OFDM schemes, TSE-OFDM exhibits ample tolerance to symbol timing offset (STO) and channel estimation errors.