OFDM系统中基于时域信号部分循环移位的低复杂度PTS算法

为了降低正交频分复用(orthogonal frequency division multiplexing, OFDM)信号的峰均功率比(peak to average power ratio, PAPR),提高系统的误比特率(bit error rate, BER)性能,提出了一种结合时域信号分割和部分子块循环移位的低复杂度部分传输序列(partial transmit sequence, PTS)算法,发送端仅需要一次快速傅里叶反变换(inverse fast fourier transform, IFFT)运算即可获得多个备选序列,接收端通过比较反向旋转序列与最近星座点的距离来恢复时域循环因子,实现了信号的盲检测。采用了两种不同的最佳序列选择准则:最小PAPR和最大相关性准则(cross correlation, CORR),并仿真分析了系统的PAPR性能和BER性能。结果表明,所提算法有效地抑制了OFDM信号的PAPR,提高了系统的BER性能,与传统PTS和选择性映射算法相比,明显降低了计算复杂度。

Low complexity PTS algorithm based on cyclic shifting partial time domain sequence in OFDM system

In order to reduce the peak to average power ratio (PAPR) of the orthogonal frequency division multiplexing (OFDM) signal and improve the bit error rate (BER) performance of the OFDM system,a low complexity partial transmit sequence (PTS) algorithm is proposed which is based on shifting partial time domain sequence. In the proposed scheme, the transmitter needs only one inverse fast Fourier transform (IFFT) operation to acquire the alternative sequences, and the receiver can restore the cyclic shift factor for blind detection by comparing with the distance of the inversed rotation sequences and its nearest constellation points. The PAPR and the BER performance of the system are analysed by using the different selection criteria for the best sequence, including minimum PAPR and maximum cross correlation (CORR). The simulation results show that the proposed method can reduce the PAPR of OFDM signal and improve the BER performance of OFDM system efficiently. On the other hand, compared with the conventional PTS and selected mapping (SLM) algorithm, the proposed method can reduce the computational complexity obviously.