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为了提高时域同步正交频分复用(TDS-OFDM)系统信道估计精度并降低其复杂度,根据时/频的对偶关系,提出了使用二值全通(BAP)序列作为保护间隔填充方案。为了进一步兼顾时域相关特性和硬件实现复杂度,提出了Legendre序列及其离散Fourier逆变换(IDFT)的保护间隔填充方案。该方案能够方便地进行时域相关以辅助接收机同步,其信道估计可以利用FFT计算循环互相关或直接利用算术Fourier变换完成。在不改变TDS-OFDM系统结构的情况下,该方案能获得更准确的信道估计。仿真表明,在频率选择性信道下误符号率较PN序列填充方案有0.4 dB左右的性能改善。
In order to improve the channel estimation accuracy and reduce the complexity of the TDS-OFDM system, a binary all-pass (BAP) sequence is proposed as a guard interval filling scheme according to the duality of time / frequency . In order to further take into account the time-domain related characteristics and hardware implementation complexity, a scheme of guard interval filling for Legendre sequence and its discrete Fourier inverse transform (IDFT) is proposed. The scheme can be easily time-domain correlation to assist receiver synchronization, and its channel estimation can be done by using FFT calculation of cyclic cross-correlation or directly using arithmetic Fourier transform. The scheme can obtain more accurate channel estimation without changing the structure of TDS-OFDM system. The simulation results show that the performance of the improved symbol rate of 0.4 dB is better than that of the PN sequence under frequency selective channel.