Introducing an OFDM-CDMA Hybrid Algorithm Based on the Multiple Access Technique to Improve Indoor Visible Light Communication Link

Transmission of information through indoor optical telecommunication systems is one of the safe methods against eavesdropping due to the non-emission of radio waves. This method is one of the   jamming-resistant techniques for military applications. In this paper, a hybrid algorithm using OFDM-CDMA based on the multiple access technique is presented. This algorithm improves the efficiency of   visible light communications (VLC) and increases the number of indoor users. The simulation results show that the BER parameter for 4 users improves from 0.035 to 0.0006 when the SNR is 0dB. Also, the bit  transmission rate for 4 users increases from 1 MB/s to 5 MB/s for SNR= 30 dB. Besides, the number of users can increase from 4 users to 20 users for the same bit rate and BER by using the proposed hybrid algorithm. These improvements were made in exchange for increasing the complexity of the system due to the wide spectrum.