Performance Evaluation of Utilizing M-Qam Ofdm With Sc- L PPM for Indoor Los-VLC Systems

Abstract

In this paper, a combination process for sub-carrier pulse modulation (SC-LPPM) technique with Mary Quadrature Amplitude Modulation OFDM (M-QAM OFDM) under distinctive and uniform lighting topologies assumption in a typical room is introduced. It was indicated from previous literatures that SC-LPPM fails to achieve the minimum performance required to achieve and sustain a reliable communication link; hence, it can be predicted that utilizing optical OFDM techniques can enhance the scheme performance allowing it to sustain a reliable communication link performance while achieving a higher operating data rate with an acceptable BER performance. However, the presented study can be more informative if the investigation is carried for different room and lighting topologies which will indicate the capabilities and the limitations of the proposed combination scheme. It can be shown in the manuscript that under distinctive lighting topology assumption, utilizing M-QAM OFDM with a single carrier modulation technique (SCM) like SC-LPPM can enhance the operating bit rate performance up to 50 Mbps with a remarkable BER performance of 8.610 -5 at modulation level (L=8), which can maintain a reliable communication link for Visible Light Communication (VLC) systems. Meanwhile, further improvement to the BER performance up to 9.5610 -6 can be achieved for the same modulation level at a 5 Mbps rate. Moreover, an investigation for the power performance of the proposed technique, the minimum required power, and the power distribution across the presented rooms topologies is presented in the manuscript under two scenarios (i.e., with and without utilizing SC-LPPM with M-QAM OFDM), which will help identifying the most suitable room and lighting layout to utilize the proposed scheme and give an insight into the performance enhancement that occurred due to the utilization of optical OFDM.