Discrete fractional Fourier transform (DFRFT) based orthogonal frequency division multiplexing (OFDM) system significantly outperforms the conventional discrete Fourier transform (DFT) based OFDM system in the presence of carrier frequency offset (CFO). DFRFT based OFDM system fundamentally involves the use of fractional transform at both transmitter and receiver. For DFRFT-OFDM, the angle of rotation (or chirp rate) should be made available to the transmitter through the feedback channel for multicarrier modulation using inverse DFRFT or IDFRFT. On the other hand, the discrete cosine transform (DCT) based OFDM system with frequency domain equalization (FDE) separately performs the task of multicarrier modulation/demodulation and channel equalization using different orthogonal transforms. In this paper, we have proposed fractional Fourier domain equalization (FFDE) for such DCT based OFDM system in the presence of CFO using DFRFT/IDFRFT replacing DFT/IDFT at the receiver. Unlike the DFRFT-OFDM, the proposed OFDM configuration is easily feasible without any chirp rate feedback to the transmitter side by replacing FDE with FFDE at the receiver. The proposed OFDM configuration significantly outperforms the conventional DCT-OFDM with FDE without any significant increase in the computational complexity.

在存在载波频率偏移（CFO）的情况下，基于离散分数傅立叶变换（DFRFT）的正交频分复用（OFDM）系统明显优于传统的基于离散傅立叶变换（DFT）的OFDM系统。基于DFRFT的OFDM系统从根本上涉及在发射机和接收机处使用分数变换。对于DFRFT-OFDM，应使用反DFRFT或IDFRFT通过反馈信道使旋转角（或线性调频率）对发射机可用，以进行多载波调制。另一方面，具有频域均衡（FDE）的基于离散余弦变换（DCT）的OFDM系统使用不同的正交变换分别执行多载波调制/解调和信道均衡的任务。在本文中，我们已经提出了在存在CFO的情况下使用接收器上的DFRFT / IDFRFT代替DFT / IDFT的这种基于DCT的OFDM系统的分数阶傅里叶域均衡（FFDE）。与DFRFT-OFDM不同，通过在接收器处将FDE替换为FFDE，所提出的OFDM配置很容易实现，而没有向发送方反馈任何线性调频率。所提出的OFDM配置明显优于具有FDE的常规DCT-OFDM，而不会显着增加计算复杂度。