Research On Index Modulation In Visible Light Communication

In recent years,with the development of mobile Internet,the demand for communication traffic has exploded.Visible light communication technology has attracted widespread attention because of its rich spectrum resources and the ability to illumination and communication at the same time.With the development of visible light communication technology,OFDM technology with high spectral efficiency and the capability of combating the inter symbol interference has become one of the indispensable technologies in visible light communication.Index modulation technology is a new modulation technology developed on OFDM.This paper mainly studies the application of index modulation in visible light communication.In this paper,the model of LED,PD and channel in the visible light communication system are studied and analyzed.Then the indoor visible light channel model is simulated and analyzed by iterative method.We study OFDM modulation schemes in visible light communication,such as DCO-OFDM,ACO-OFDM,NDC-OFDM,etc.,and verified their bit error rate performance by simulation.In this paper,the principle and method of index modulation are studied in detail,and the carrier selection scheme and detection algorithm in index modulation are analyzed.Two kinds of index modulation schemes IM-DCO-OFDM and DM-DCO-OFDM applied in visible light communication are further compared.The system performance of the two modulation schemes is verified by simulation.In this paper,a new index modulation scheme OIM applied in visible light communication is proposed.In the proposed scheme,index bits are used to select the combination of transmission of two unipolar PAM signals on each subcarrier.The receiver recovers the index bits and the constellation bits separately.This method can avoid an error in the constellation de-mapping caused by the error judgment of the carrier pattern.In this paper,the proposed index modulation is combined with DCO-OFDM and NDC-OFDM schemes,and two modulation schemes of OIM-DCO-OFDM and OIM-NDC-OFDM are proposed.The simulation results show that OIM-DCO-OFDM has better bit error rate performance than DM-DCO-OFDM under the same spectral efficiency.The simulation proves that OIM-NDC-OFDM can use the smaller order constellation modulation to achieve the same spectral efficiency and bit error rate performance as NDC-OFDM.