Synchronization and channel estimation for optical block-transmission systems with IM/DD

The timing synchronization of OFDM/DMT systems is often based on auto-correlation algorithms. However, these algorithms do not provide a sharp correlation peak. In this work, we present a novel timing synchronization and channel estimation concept for optical block transmission systems with intensity modulation and direct detection. This concept is based on Golay complementary sequences. As these sequences are binary, multiplier-less matched filters can be implemented in order to use the cross-correlation function for the timing synchronization. Since Golay complementary sequences have ideal correlation properties, they enable an estimation of the channel impulse response directly in the time domain. We present an appropriate preamble structure and receiver concept for PAM-block transmission systems with frequency domain equalization and demonstrate the performance exemplary for 7B8B-coded binary PAM.