DCO-OFDM系统DCT-S峰均比抑制算法

针对直流偏置光正交频分复用（DCO-OFDM）系统中的非线性失真问题，提出一种基于离散余弦变换（discrete cosine transform，DCT）和缩放（scaling）的DCT-S峰均比（PAPR）抑制算法。该算法通过DCT改变功率分布概率，减小信号包络范围，再对时域信号进行自适应缩放，使其更好地适应LED的动态范围，降低系统峰均比，进而抑制了非线性失真。仿真结果表明，与传统算法相比，该算法在LED发射功率不变的前提下，大幅降低了DCO-OFDM系统的峰均比，同时降低了误码率。

DCT-S peak-to-average ratio suppression algorithm in DCO-OFDM system

Aiming at the nonlinear distortion problem in DC offset optical orthogonal frequency division multiplexing(DCO-OFDM) system, this paper proposed a DCT-S peak-to-average ratio(PAPR) suppression algorithm based on discrete cosine transform(DCT) and scaling. The algorithm changed the power distribution probability by DCT transform to reduce the signal envelope range. And then adaptively scaled the time domain signal to better adapt to the dynamic range of the LED, reduced the system peak-to-average ratio, and thus suppressed the nonlinear distortion. The simulation results show that compared with the traditional algorithm, the algorithm could greatly reduce the peak-to-average ratio of the DCO-OFDM system and reduce the bit error rate under the premise of the LED transmit power.