Throughput Improvement Using Code Length Optimization for VLC-OFDM/IDMA

This paper proposes a joint channel ranking and successive interference cancellation (SIC) scheme for Interleave Division Multiple Access (IDMA) based Orthogonal Frequency Division Multiplexing (OFDM) on Visible Light Communication (VLC). With the spreading LEDs, VLC has been gaining attention as an effective communication means. Propagation medium of VLC is tremendously higher frequency electromagnetic waves than terahertz and hence VLC has superiority in terms of communication directivity and security. Under the use of VLC-OFDM, joint application of IDMA and spreading codes has been previously proposed for uplink multiple access scheme which can exhibit superior multiple user identification capability. However, it substantially requires large spreading factor as well as lower coding rate for error correction; achievable throughput performance was limited. In this paper, we introduce a channel ranking and variable spreading factor to improve the system throughput performance while maintaining BER degradation. Effectiveness of the proposed approach is clarified through computer simulation.