OFDM/OQAM based WDM fiber VLLC system employing improved channel estimation method

In this paper, we propose and experimentally demonstrate an OFDM/OQAM based WDM fiber visible laser light communication (VLLC) system employing improved channel estimation method. The improved channel estimation method is based on conventional interference approximation method (IAM) combined with the discrete Fourier transform (DFT) based channel estimation (IADF-CE). It is used to mitigate the intrinsic imaginary interference (IMI) and noise from the estimated channel response for OFDM/OQAM signal. Enabled by IADF-CE scheme, 1 dB and 1.2 dB power penalty improvement can be achieved in comparison with conventional IAM after transmission over 50 km standard single mode fiber (SSMF) and 4.5 m free space link for 16 OQAM and 4 OQAM modulations, respectively. Furthermore, each user can achieve a maximum aggregate data rate of 3.2 Gbps under the bit error rate (BER) of 2.7×10−2 in the system.