Joint codebook assignment and power allocation for SCMA based on capacity with Gaussian input

Sparse Code Multiple Access (SCMA) is a non-orthogonal multi-dimensional spreading technique based on layered codebooks. In SCMA, incoming bits are directly mapped to multi-dimensional codewords of pre-defined codebooks. In comparison to simple repetition of QAM symbols in Low Density Signature (LDS), shaping gain of the multi-dimensional constellation is the main advantage of SCMA for performance improvement. Similar to LDS, SCMA can take the...