4 research outputs found
SCMA with Low Complexity Symmetric Codebook Design for Visible Light Communication
Sparse code multiple access (SCMA) is attracting significant research
interests currently, which is considered as a promising multiple access
technique for 5G systems. It serves as a good candidate for the future
communication network with massive nodes due to its capability of handling user
overloading. Introducing SCMA to visible light communication (VLC) can provide
another opportunity on design of transmission protocols for the communication
network with massive nodes due to the limited communication range of VLC, which
reduces the interference intensity. However, when applying SCMA in VLC systems,
we need to modify the SCMA codebook to accommodate the real and positive signal
requirement for VLC.We apply multidimensional constellation design methods to
SCMA codebook. To reduce the design complexity, we also propose a symmetric
codebook design. For all the proposed design approaches, the minimum Euclidean
distance aims to be maximized. Our symmetric codebook design can reduce design
and detection complexity simultaneously. Simulation results show that our
design implies fast convergence with respect to the number of iterations, and
outperforms the design that simply modifies the existing approaches to VLC
signal requirements
Experimental demonstration of SCMA for visible light communications
We propose an experimental demonstration of sparse code multiple access (SCMA) based visible light communications (VLC) system, in which the multi-dimensional codewords selected from a predefined codebook set are used to encode the transmitted data and a message passing algorithm (MPA) based multi-user receiver is used to detect the multiplexed codewords. Compared with the orthogonal frequency-division multiple access scheme, the SCMA scheme offers 150% overloading gain in the number of supported users at the cost of slightly decreased transmission performance