Research On Key Technologies Of PON-VLC Heterogeneous System Based On Index Modulation Orthogonal Frequency Division Multiplexing

With the increasing popularity of information technology services such as cloud computing,Internet of Things,big data,and virtual reality,traditional fixed and wireless access networks are facing the challenge of increasing bandwidth index.Passive optical network-visible light communication(PON-VLC)heterogeneous communication combines the advantages of optical fiber communication and visible light communication with wide bandwidth,anti-electromagnetic interference,flexible and safe access,etc.,and has attracted the attention of scholars.Orthogonal frequency division multiplexing(OFDM)has been widely used in the fields of wireless communication and optical communication due to its high spectral efficiency and anti-dispersion effect.Index modulation OFDM is a novel modulation technology developed on the basis of OFDM technology.This technology not only reduces the peak-to-average power and inter-carrier interference of traditional OFDM,but also further improves the spectral efficiency.In this article,index-modulated OFDM is applied to the PON-VLC heterogeneous communication system,and the main work is as follows:1.In this paper,considering that the low spectrum efficiency caused by a large number of inactive sub-carriers in traditional sub-carrier index modulation OFDM(SIM-OFDM),an OFDM model based on subcarriers index power modulation(SIPM)The full-duplex PON-VLC heterogeneous communication system is proposed,and the system is simulated and verified.The simulation results show that after 35 km standard single-mode fiber transmission and 5m free space uplink and downlink bidirectional transmission,the constellation of the SIPM-OFDM signal is still clear.Subcarrier power modulation index-modulates all subcarriers,which has higher spectral efficiency,and only needs to make power decisions at the receiving end,so the structure of the receiver is simple.Meanwhile,the vertical cavity surface emitting laser(VCSEL)used in this system,which has the advantages of high modulation bandwidth and low cost.2.In this paper,to further improve the frequency efficiency of traditional dual-mode index modulation OFDM(DM-OFDM),a PON-VLC heterogeneous communication system based on the subcarrier index-power joint modulation OFDM model is proposed,and the system is simulated and verified.Subcarrier index-power joint modulation OFDM uses all subcarriers to transmit symbol information.Not only does it use subcarrier position index bits to transmit additional information,but it also combines subcarrier power modulation to further increase the spectrum efficiency of the system.