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At the physical layer, sparse code multiple access (SCMA) technology is used to solve the problem of massive user access.In the current research on SCMA, in addition to the research on SCMA multi-user detection technology, more attention will be paid to the design of SCMA system codebooks.SCMA codebook with good performance can not only improve its anti noise performance in the process of multi-user detection, but also reduce the detection complexity.The traditional codebook design scheme is mainly researched on low-dimensional codebooks, and most of the designed codebook schemes are based on QAM, TCM, and Lattice, while few people have set foot in and studied high-dimensional codebooks.A new codebook design - Golden Angle Modulation (GAM) was mainly focused on, and on this basis, proposed a Variable Bit Rate (VBR) GAM codebook design method.The simulation results showed that the VBR-GAM codebook could fl exibly met the needs of diff erent services.With the increased of the modulation order, the VBR-GAM codebook had better performance than the traditional GAM codebook. |
