  Sparse code multiple access (SCMA), as a code-domain non-orthogonal multiple
access (NOMA) scheme, has received considerable research attention for enabling
massive connectivity in future wireless communication systems. In this paper,
we present a novel codebook (CB) design for SCMA based visible light
communication (VLC) system, which suffers from shot noise. In particular, we
introduce an iterative algorithm for designing and optimizing CB by considering
the impact of shot noise at the VLC receiver. Based on the proposed CB, we
derive and analyze the theoretical bit error rate (BER) expression for the
resultant SCMA-VLC system. The simulation results show that our proposed CBs
outperform CBs in the existing literature for different loading factors with
much less complexity. Further, the derived analytical BER expression well
aligns with simulated results, especially in high signal power regions.
