LAUSR

Abstract This paper presents a peak to average power ratio (PAPR) assisted non-data aided feedforward fast Fourier transform (FFT)-based frequency offset (FO) estimation algorithm for 32-ary quadrature amplitude modulation (32-QAM) coherent optical systems. In our proposed algorithm, rotation and amplification operations are adopted in addition to traditional FFT-based FO estimation algorithm. And the amplification coefficients are designed to achieve the maximal PAPR of the spectrum. Simulation results show that no estimation error occurs when the signal to noise ratio is above 17 dB with the data length of only 512. And at the 20% forward error correction threshold of BER = 2 × 10−2, our proposed algorithm shows a penalty of only 1.2 dB with respect to the theoretical limit.