稀疏码多址接入，就是应5G需求设计产生的一种非正交多址技术。在发送端通过多维调制和稀疏扩频将编码比特映射成SCMA码字，接收端通过多用户检测完成译码。-Sparse code multiple access is a kind of non orthogonal multiple access technology, which should be produced by the design of 5G demand. The coding bits are mapped into SCMA code word by multi dimension modulation and sparse spread spectrum at the transmitter end.